Star tuned magazine june 2008


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Star tuned magazine june 2008

  1. 1. TO OUR READERS IN THIS ISSUEWel come to StarTuned, t hemagazine for independent service 4 CLEAN STRAIGHT AND CLAMPEDtech nicians wo rking on Me rce des- One of the benefits of owning a Mercedes-Benz has alwaysBenz ve hicles . You r Merce des-Benz been longevity. But after many years of f lawless se rvice, theredea ler sponso rs StarTuned and is a chance that head gasket failure wil l occur. The value of aprovides t he information com ing Merce des-Benz makes it worth repairing.your way in eac h issue .Mercedes-Ben z wa nts to prese nt th e 12 AIC PRINCIPLES AND CONTROLSinform ation you need to know to Summer is almost upon us, and with th e warmerdiagnose and repair Mercedes-Benz weather com e customers hot under the collar abou tcars acc urate ly, qu ick ly and th e fi rst air conditioning performance.t ime; text, graphics, on-l ine and othertechn ica l sources co mbin e to makethi s poss ible. 22 CUSHIONING THE BLOW - PART 1Feature articles, derived fro m As always, at Mercede s-Benz the top priority is t he safety ofapproved company sources, foc us the people who drive its vehicles . Airba g systems need to beon be ing useful and interesting. maintained and se rviced to ensure the same level of safetyOur digest of technica l inform ation that the engineers intended.can he lp you so lve unant icipatedprob lems quick ly and expert ly.Our list of Me rcedes-Benz dea lerscan he lp you f ind Ge nuin e 28 SMALL REPAIR, BIG OPPORTUNITYMerce des-Benz Parts . One of the benefits of owning a Me rcedes-Be nz is theWe want StarTunedto be both timeless style it exhibits. With bodies an d interiors sc ulpte dhelpfu l and info rmative, so please let like artwork , its no wonder their owners ta ke pride in th know ju st what kinds of featuresan d other diagnostic services yo u dlike to see in it. We ll continu e to 30 FACTORY SERVICE BULLETINSbring you selected service bullet ins These suggestion s and solutions for technical problems arefrom Mercedes-Benz and arti cles from service bull etins and other informatio n pub lished bycove rin g th e different systems on Merced es-Benz, se lected and adapted for ind epen dentth ese ve hicles. repair shops.Send yo ur suggestions, questi onsor comments to us at:StarTuned 31 GENUINE MERCEDES-BENZOne Me rcedes Drive PARTS ... NEARBYMontva le, New Jersey 0 7645 Wherever you are in the United States, theres a nearbyPhone : 1 800 225 626 2, ext. 711 2 source of ge nuin e factory parts for your customerse-mail: m Merce des-Benz ve hicl es .StarTuned is a quarterly publication of Mercedes-Benz USA, LLC ("MB USA") . No part o f t hi s news letter may be reproduced without the express written permission ofMBUSA. Editorial and Circulation Offices: 598 Pine Po int Dri ve, Akron, Oh io 44333. Caution: Vehicle servicing performed by untrained persons could resu l t i n ser iousi njury to t h ose pe r sons o r others. Informat ion conta in ed in this news letter is intended for use by trained, profess ional auto repair technic i ans ONLY. Th isinformation is p r ov i ded to i n form these techn i c i ans of condi ti o n s wh i c h may occu r in so me veh ic les or to provide info rmation which could assistthem in proper servic ing of these veh ic l es. Pro per ly tra in ed techn icians have the equipment, too ls, sa fety instruct ions, and know-how to perform repairscorrectly and sa fely. If a cond ition is described, DO NOT assume that a top ic covered in these pages automat ica ll y app li es to you r veh ic le or that you r vehicle hasthat condition. StarTuned is a registered trademark of MBUSA .
  2. 2. STARTUNEDInformation for the Independent Mercedes-Benz Service ProfessionalJune 2008 U.S. $6.00 € 1 2.50 Volume 8 Number 2Group Publisher Contributing Editor MBUSA Technical Production ManagerChristopher M. Ayers, Jr. Wade Nelson Content Advisor Devon Donald Rotolo dayers@cmacomm .com Donald.Rotolo@mbusa.comSenior Project Director Contributing Editor Circulation ManagerTamra Ayers Kerry Jonnson MBUSA Project Manager Joann Turnertayers@ cmacomm .com kjonnson@ Russel l G. Chave j Russe ll .Chave@mbusa .comEditorial Director Contributing Editor List ConsultantBob Freudenberger Ray Fisher Art Director rayfisher@ Jef Sturm jsturm@
  3. 3. Clean, Straightand Clamped:Head Gasket Diagnosisand Replacement
  4. 4. Aside from swapping an entire engine and/ortrans mission, rep lacing cy li nder head gasketsis pro bably one of the more time-co nsuming job syou perform. Looking at labor times, a typ ica lcylinder head R&R procedure can ta ke 10 to 15hours for a straight four or six, and up to 25hours for a V8 or V12. The job represents asign ificant investment on the part of thecustome r. So, when yo u diagnose a failed headgasket you need to be confident that this wil laddre ss the customers concerns. Some fa il uresare straightforward, but on the more difficultones you need methods to ve rify yoursuspi cions. Here, we ll look at how headgasket s fail , symptoms of fai lure, and foo lprooftestin g methods, and review some importantpro ced ura l points. Pressure testing the cooling system may force coola nt through a leaking cylinder head gasket. With a boro- scope you can see into the cylinder and observe if there is any coolant seepage. StarTuned 05
  5. 5. How Head Gaskets Fail Head gasket failures can occur in several different ways. The fluids that pass through the gasket are either oi l or coolant. Pressurized oil is sent through the gasket on its way to lubricate the valve train. It then dra ins back through the cyl inder head into the crankcase. Coolant also passes through the cylinder head passages and the block to keep these components cool. As with any gasket, the one between the head and the block is meant to sea l fluids in. The oil pressure passing through the head and the oil draining back to the block needs to be contained by the gasket. Any externa l leak of oi l would be considered a head gasket failure. By the same token, any external coo lant leak would also be a head gasket failure. Not all leaks have to be external. The failures that are not visible are often the ones that have to be diagnosed. They require more in-depth testing. Head gaskets may fail with the oil pressure supp ly line breaching its gasket and entering the coo ling passage . Oil pressure is usual ly higher than cooling system pressure, so oi l is forced into the cooling system. If the oil return passage leaks, you may end up with coolant in the crankcase. Another instance is a high-pressure oil system leaks into the combustion chamber.Using a combustion gas Probably the most tel l-tale sign of a bad head gasket is coo lant entering the combustionleak detector will allow you chamber. This problem causes many symptomsto determine if theres a leak from high pressure in the coo ling system resu lt ing in blown hoses and leaks to steambetween the combustion exiting the exhaust. Techn icians naturally thinkchamber and the cooling of th is situation first when head gasket failure is mentioned, but as already mentioned this is notsystem. Dont fo rget to drain the only type of failure. So, other than vis iblesome coolant out of the leaks or steam, what are the symptoms that ind icate head gasket fa ilure?system to build up sufficientcombustion gas. Tipoffs We have discussed engine oil in the coolant and coo lant in the oil. Another common-sense item is the coo lant leve l. Very often we add coo lant, check for external leaks and move on. We ll , the coo lant had to go somewhere so06 StarTuned
  6. 6. Here we can see the swirl marks left by surfaceconditioning discs. If you stay in one portion of the cylinderhead too long you can create a dip that the head gasketmay not be able to seal. So, clean the cylinder head byhand using suitable scrapers.further investigation is warranted . Did an over- symptom. Combustion gases gettin g into theheating problem cause the low coo lant cond iti on , coo lin g system can co llect at a hi gh point, and ifor did a low coo lant condition cause the it so happens that this is where the CTS (Coolantoverheating? Temperature Sensor) is located, the sensor may Overheating is one of the major symptoms be exposed to gases instead of liq uid. This couldof head gasket issues, espec iall y if you do not cause the sensor to change its resistance value,see any signs of external coo lant loss. If you hence its signa l, rapidly, and be an earlydo have a leak, you may need to look deeper indication that somethin g is wrong with theanyway. Sometimes a leak is just a leak, but coo ling system.excess ive pressure in the coo lin g system w ill Fin all y, a driveab ility prob lem may be an issuepromote and en large leaks. Of course, there are that has more to do with engine temperaturemany possible reasons for overheating, but it s than the fuel inj ection and ignition systems.always a good idea to test for head gasket fail - Cylin der misfires can be caused by coolant leak-ure before (or even after) coo lin g system in g into a combust ion chamber. Mercedes-Benzrepa irs. After all, if the overheat in g was engin es are known around the world as some ofsevere enough it may have warped the best, but lack of proper ma intenance, use of low-cylinde r head casting(s) . octane fuels and long periods of time in stop and If you r customers concern is an erratic go traffic can contribute to premature failure oftemperature gauge, this may be another various components, such as the head gasket. StarTuned 07
  7. 7. HEAD GASKETSTesting, Testing, Testing, ... is a good idea to test under both cond it ions. A head gasket may leak when cold, but not when He re is where it may get ugly. You have a veh i- hot, and the opposite is also true. If you pres- cle come in thats running a little roughly. Maybe sure test the system and get noticeable white the Ma lfunction Indicator Lamp (M IL) is f lash ing, "smoke" (actua ll y steam) out of the ta ilpipe, one indicating a misfire, or theres a message in the or more cylinders are leaking coolant into theinstrument clu ster message center indicating combustion chamber. If you have a boroscopethat the PCM has detected a problem. You eva lu- that allows you to look into the spark plug holes, ate the service records and see that a tune-up you may be able to actually see the leak whilemay not have been performed in quite a whi le. the system is pressurized. Using Star Diagnosis,Maybe the customer has forgotten about the or an approved scan tool, you can look at mis- 60,OOO-mile service, or has just been resetting fire data. Th is may help indicate what cy lindersthe "ASSYST" warn ing system, wh ich indicates are the like ly cu lprits.the need for ma intenance. Whatever the reason, If the symptoms are minor, finding a headyou inform the customer that maintenance serv- gasket leak will be more difficult. The best way toice is due , and you perform the tune-up. A con- test for a sma ll compression leak is to use asiderab le amount of money must be spent, but "chemical block tester." This contains a chemicalthis is a Mercedes-Benz and the customer clearly solution in a mu ltiple diaphragm syringe. Gasessees that the veh icle is worth the requ ired invest- in the cool ing system are drawn into the tool andment. The problem occurs when the symptom mixed with the solution. If combustion gases arecomes back. Now, your reputation is damaged, present, these chemicals change color. To get anand you have to dig a little deeper. accurate read ing you need to dra in approximate- You may have tested the coi l by check ing its ly one ha lf to one fu ll ga ll on of coo lant from theoutput with a spark tester (HE I type), or rep laced system, depending on its tota l volume. Thisit anyway. You could change the position of the all ows a sufficient quantity of gases to bu ild upco il (in coil-aver-p lug configurations) and see if in the coo lant reservo ir and the radiator fo r thethe problem moves. If not, you may perform a leak detector to work. Overlooking this step is"fue l pressure drop" test on the injector and/or likely to lead to fa lse readings and an erroneouschanged its location as well only to f ind the prob- diagnosis.lem is still in the same cylinder. Providing it isnot a defective new spark plug (what are theodds of that?), the problem must be in the cy li n-der. A compression test may indicate an accept- Now For the Hard Workable amount of pressure, but a leak-down testmay te ll you a bit more. Low compression on two Once you have determined that coolant isadjacent cyl inders typ ically means the gasket indeed getting into the combustion chamber, itsbetween them has failed. Through a process of time to start the disassembly phase. At this pointelimination, you have determined all other it wou ld be wise to inform the customer thatcomponents are performing as they shou ld, but although it looks like the head gasket has failed,you still have a misfire. You need to look at the there cou ld be other causes such as a crackedpossibility of coo lant leaking into the block or cyli nde r head. There is no way of know- combustion chamber. ing until disassemb ly has been completed and Pressure testing the coo li ng system is a good the various components checked for cracks. way to find leaks, inc luding leaks into the com- Depending on the age of the vehicle, this may bustion chamber. Head gaskets survive also be an opportunity to renew various engine admirab ly under tough condit ions. They need to components. The cylinder heads themse lvesseal when the engine is both co ld and hot. So, it could be exchanged for units refurbished by08 StarTuned
  8. 8. After cleaning, measure the surface straightness of the cylinder head matingsurface. In this case it was necessary to mill the cylinder head, and the headthickness was sufficient to do so. This creates a near ideal surface fo r the headgasket to seal against. Getting Cleaned UpMercedes-Benz. If you are equipped to rebuildthe cyl in der heads, you can perform the task Clean in g the cy lind er head gasket surfaceyourse lf. Even if you do not have the equipment properly is critica l. Aluminum is so soft, it s easyto cut the val ves and va lve seats, you can to ruin a head casting with electri c or pneumaticremove t he va lves and lap them in . Cylind er head tools in a matter of seconds. Do not use Scotchgasket sets typically include va lve guide seals, so Brite pads on yo ur "whizzer" too l as they willreplace them by all means. Timin g chains need cause gouges and undulations, and leaveto be removed in order to perform the head abrasives behind that can actua ll y damage bear-gasket j ob, so a new tensioner wou ld be a good in gs. Ditto for the sea ling surface of the block.idea. Replacing the timing chain itse lf wo uld be Soak in g the head in a distillate so luti on causesadvantageous from a labor saving standpo int. the gasket remnants to soften for easier rem ova l. After removing t he t imin g chain, and the intake The use of a properly sha rpened gasket scraper,and exhaust systems, (sometimes its easier to free of gouges itself, wi ll remove most of theremove the cylinder head wit h the exha ust material left on the head.and/or intake manifolds sti ll attached), we can Next, acc urate measurements must be takenthen unscrew the head bolts. With aluminum for surface flatness and irregularities. Th esecylinder heads, Mercedes-Benz recommends that measurements, along wit h t he overa ll t hicknessyou crack each bolt loose in four stages of about of the cy lind er head, will determine if the casting,90 deg. each. Thi s prevents any warp in g of the sim ply needs to be clea ned, or must be mill ed orhead, espec ially on a warm motor. Once the replaced. Hold a straight edge tool against th ebolts are out, t he castin g is still "glu ed" to the block and cylin der head in multiple positions andblock by the sea l of the head gasket. You need to measure the depth of any gaps with a feelerfind a safe point to pry the cylin der head from gauge. If excessive "waves" or "rippl es" aret he block, th en yo u can safe ly lift off the cyl ind er found, t he head or block must be milled tohead assembly. assure a good sea l. StarTuned 09
  9. 9. HEAD GASKETS Look at the two cylinder head bolt holes on this 190 model and you can see that the one on the lower right is cleaner than the one on the left. Do not use a tap to clean bolt hole threads. You will remove too much material. Use thread cleaners or chasers and you will have a secure mating of the thread surfaces. You should also be concerned with the head document AH01.30-P-bo lts. Since torque-to-yield bolts are used 1000-0 6V, there are two different dimensions in(mean in g they stretch), Mercedes-Benz has the compress ion rin g of the cylin der head gasketincluded a spec ification on head bolt length. for the 11 2 and 11 3 engines found in the 210If the head bolt has stretched beyond th is spec, chass is. Th ey are distinguished by one or twothen the possibility exists that th e bo lt will notches found on the outside of the timing chainbottom out in the block and the head bolt will passage of the gasket. If the smaller dimen sionnot apply the necessary clamp ing force to the is used in th e larger application the piston maycylinder head allowing it to wa rp when the contact the gasket and create a knocking noiseengine gets up to operating temperature . Or, at idle. Does the aftermarket head gasketth e bo lt may simply snap, wh ich wou ld resu lt in supp li er make th is distinction?a time-consuming extraction job. After returning any dowels to the engine block that were removed for cleaning, locate the head gasket properly and carefully lower the cy linderReassembly head into place. Of course, the cylinder head bolts must have the proper torque applied in Now is the time to choose what kind of four stages to ensure the casting is pul led downgasket you re going to use to reassemb le the evenly and the gasket receives uniform clampingengine. Remember, genuine Mercedes-Benz force. Fo ll ow the published service procedurereplacement parts use the same design, materi- carefu ll y. Th e same process applies to any otherals and construction as the origina l - and look large gasket surfa ce such as the intake andhow long it lasted . The cost is competiti ve with exhaust manifold s. Insta ll the timing chainaftermarket brands that simply cant come up to accord ing to service procedures outlined in WIS.Me rcedes-Benz standards . Thi s is not a job you Rotate the cranks haft a few times to verify thatwant to do over again. the tim ing chain is instal led properly. Acco rding to Mercedes-Benz WIS-net Yo u can fin ally co nnect auxi li ary devices and(accessib le through a pa id subscription to components, fill with fluid s and check for leaks. 0 StarTuned
  10. 10. Enticingly graceful and dynamic. Strong support, too. QUALITY FIT PERFORMANCE VALUE SERVICE WARRANTY EllelY part comes with lhe reassurance of a siron;; 12·monlh/unlimiled·milea!?11 limitlli/ l1armnty - with (I(/diliurw/ wVI!mge for en;;ines and transmissions: Unlike any other.The part is just part of the story. The precise fit and superior performance of a Genuine Mercedes-BenzPart is a given. But equally important is that each Genuine Mercedes-Benz Part - down to the last nut,bolt and gasket - comes with the unmatched technical support and expertise from your dealer andMercedes-Benz. All evidence of our constant dedication to supporting your business in more and betterways than anyone else. And thats the best part Visit or contact your dealer. Mercedes-Benz•StlR. your Mercedes-Benz denier rortl~((JiL~ anti (l ropy t){cllB 11IIeJr.(>.(Ie..:rBenz Replacement PafL<i Llm[w..t} l-ItlflYllUY.
  11. 11. FEATURE ARTICLE Ale Principles a 2 StarTuned
  12. 12. nd Controls Summer is almost upon us, and with the warmer weather come customers hot under the col/ar about air conditioning performance. Advancements in technology are everywhere. temperature of the refrigerant is increased as we ll . From computer-controlled systems to new This hot pressurized gas is sent to another materia ls, the automotive industry is march ing component cal led the condenser. The function forward to provide lower em issions, increased of the condenser is just that. It functions like a safety and more creature comforts. The creature radiator - air flows over its fins and tubes comfort in question here is Automatic Air cooling the contents. As the refrigerant cools it Conditioning (AAC), which provides more condenses into a high pressure liquid and exits efficient cool ing of the cabin. Driver, passenger, the condenser. The refrigerant then passes and even rear passengers (Thermotron ic) can through what is ca ll ed a receiver Idryer. This each enjoy their own persona l space, at least component filters out impurities in the refrigerant when it comes to temperature regu lation. charge, both chemica l and physica l debris. As a technician you may feel these advance- The next component this high pressure liquid ments come at the price of added complexity in passes through is, in the case of Mercedes-Benz diagnosis and difficulty of service, but this is vehicles, an expansion valve. Its job is to meter not entirely true. Yes, the systems are more the liquid through an orifice, forming a low-pres- compl icated, but the basic princ iples of air sure liqu id. This low-pressure liquid now enters cond itioning still apply. All you need to know is the evaporator core. Th is is where refrigeration how the advancements improve system actua lly takes place. As the low pressure liqu id operation and take them into account, passes through the evaporator core it changes particularly during troubleshooting. state and absorbs the heat in the air around it. A blower motor forces either fresh air from Basics outside the car, or recirculated air within the cabin, through the evaporator core and the core In order to understand the changes in air absorbs the heat in the air. Its sort of like a conditioning systems over the past few years we radiator, but it works backwards. Instead of the first need to have an understanding of the most heat of a liqu id being dissipated into the basic principles. We will start with what is consid- airstream, its the other way around. As the ered the heart of the air cond ition ing system, the low-pressure liqu id absorbs the heat of the cabin AIC compressor. Its function is to take the it evaporates and becomes a low-pressure gas. mechanical energy of a runn ing engine and con- Th is passes back through the expansion valve, vert it into a pumping action that moves refriger- giving the expans ion valve an ind ication as to ant throughout a closed system. It takes in a low how much heat is being absorbed (load) and pressure gas and pressurizes it into a high pres- opens and closes the va lve accordingly. Finally, sure gas. During this process, due to the compres- the low-pressure gas is returned to the compres- sion of the gas and the friction created, the sor and the process begins allover again . StarTuned 13
  13. 13. AIR CONDITIONINGAutomatic Air Conditioning (AAC) The purpose of AAC is to control temp erature and direction of airflow accord in g to th e occ u- pants desires . Thi s is accomp li shed by using compute r contro ls to monito r ca bin co nd itio ns and outside temperatures, and to provide t he changes requ ired to respond to occ upant requests. Lets look at th e t yp ica l playersinvolved in this symphony of cli ma te co ntro l.The first component we wi ll discuss is theclimate control computer. This is the brain of thesystem, both mon itoring input and ma nipulatin goutputs to respond to the passenge rs needs .The contro l un it can be on its own, or, in t hecase of most Mercedes-Benz veh icles, can beinco rporated into the co nt rol panel in the veh icle. Se lf-d iagnostic fu ncti ons have also been in co rpo-rated in their des ign. Next on our list are t he enviro nmental senso rs. By positioning the drivers side temp toThese relay information back to the com puter.They indicate air tem peratu re outs ide the ve hicle, high, the passenger side to low andinside the ve hi cle (in the case of dua l zo ne pressing the "ECON" and "REST" but-climate control, the te mperat ure in bot h t hedrivers side and passengers side ducts). tons, you can have this AAC control unitMercedes-Benz has also in co rp orated a sun loa d display codes. You can also commandsensor that mon ito rs ambi ent su nlight andadjusts air co ndition ing co ntrols to co mpensa te output control and read sensor values.for it. More input sensors are use d to co ntro lbot h the A/C system and heating systems . A/C more temperature co ntrolled zo nes in t herefrigerant switches/se nso rs are used to monitor ve hicles inte ri or the more sensors and motorsrefrigerant press ure and te mpera ture to co ntrol will be add ed, but the ir basic opera tio n will becompressor operation, hence te mperat ure. As ide the sa me. Up until rece ntly most of these "modefrom read ing refrigera nt tempe rat ure and pres- door" contro ll ed outputs we re hand led with asure in the lines, there are also se nso rs that read system that used engine vacuum and redirectedthe temperature of the evapo rator. Thi s tell s the it to va ri ous diaphragms under the dash,contro l un it when the evaporator core is st artin g attac hed to th e HVAC control assembly, toto freeze so the AAC unit can preve nt ice from cha nge airflow directi on. Th ese systems haveforming and blocking air flow. Add itional senso rs since bee n replaced with electric motors thatinclude a Multifunction sensor th at passes on co ntrol mode door operat ion. In the past ahumidity information to the AAC un it. mec han ica l leve r positi oned a doo r th at co n- On the output side of t he eq uati on is th e t ro ll ed th e temperature by mixin g th e coo l air of compressor clutch (not eve ry veh icle has one), the A/ C syste m with the hea ted air of t he heater so lenoids and mode doo r motors. Th ese outp uts co re. With ACC, the co ntrol un it operates an contro l when the compressor cyc les on and off, electric mot or blend door (or two , or more) inhow much heated coo lant will be all owe d into response to changes in sun light , ambi entthe heater core and what vents th e airflow will te mp erature and occ upa nt request s. Th esebe directed out of. As ment ioned ea rlier, th e motors also provid e feed back as to the ir position1 StarTuned4
  14. 14. With a paid subscription to www.startel< you have access to facto- ry wiring diagrams. In this diagram for the S-C/ass (220 chassis), 1001< at the wiring for the left SAM. If you follow the wire from component N I0/6, youll see that it controls the AIC Compressor Control valve.for diagnostic purposes. When repla cing these anywhere from 125 to 350psi. These pressuresmotors or the AAC control unit you wi ll need a show the compressor is capab le of creatingfactory scan tool, or equivalent, to ca librate the suction on the low side and generatin g highmotor positions. pressure on the high side . What do we do when the A/C system perform-PSI ance is not up to snuff? We check these pres- sures. If the pressure of the high side gas is too One of the most basic test s yo u ca n perform hi gh we suspect a restriction in the system. Onon the hardware of the A/C system is monitoring the high side, thi s can either be a clogged receiv-the high and low sid e pressures . As we dis- er/dryer, or a stuck-closed expansion va lve . Ifcussed earlier, the refrigerant system is broken the high side pressure is too low, then most like lydown into four phases: high pressure gas, hi gh the expansion va lve is stuck in the open position.pressure liquid, low pressure liquid and low pres- There are diagnostic flow charts provided bysure gas . Monitoring these pressures will indicate Mercedes-Benz that outline the testing of basicif the re is a problem in the system and where the pressures and the problem s associated withprob lem may be. Typi cally, Schrader va lves are variou s readings . Th ese pressure charts haveconven iently mounted in th e air condit ioning been used for years on basic A/C systems.lines on the hi gh- and low-pressure sid es of the In the mid-90s Mercedes-Benz started to usesystem. They allow you to mon itor the gas variabl e-d isplacement compressors. These use apressure in the system whi le it is operatin g. By moveable swash plate that ca n change the pistonmonitoring both sid es of the system you can stroke trave l. Thus, in high lo ad cond itions theusually get a good idea of what the performance displacement of the compressor can beproblem may be. We have al l been taught that increased and for low load situations it can bewith a proper refrigerant charge th e low side of decreased. Thi s allows greater contro l ofthe system ca n be pulled down to 20 to 30psi. compressor load as the engine rpm changes inThe high side pressure will increase more respo nse to the drive rs demands. As a resu lt ofdepending on ambient temperature and can run th is design change, yo u need to know the StarTuned 15
  15. 15. AIR COND ITION ING When looking for the compressor in a wiring diagram from website, you need to know that it will be found in section 54 Electrical Systems - Equipment and Instruments. In the case of this 220 chas- sis, the left Signal AcquisitionModule controls the Ale com- pressor. Trace the wiring for component A9. position of the swash pla te if yo u are going to and AIC co mpresso r output. This is also how the use pressures to determin e what is wro ng with co mpressor is shut off. Wi th t he contro l va lve at the system. In additi on to knowin g the hi gh and 2%, it is wide open and the hi gh pressure low side pressures, yo u will need to know th e red uces the piston stroke to ni l, eliminating co mm and from the AAC co nt rol unit fo r t he co mpresso r output but stil l keeping t he internals swash pl ate position . There is no feedback on lubri cated. If t he low side pressure goes above swash pl ate position, so you wi ll j ust have to that of t he diaph ragm, the AIC Compressor monitor the pressu re change relative to t he Contro l va lve is ope ned up to 100%. Th is al lows command change by increasing AIC re quest the swash plate to move to a position increasing through t he contro l pa nel (lowe rin g req ueste d piston stroke and ove rall pressu re in the high AIC tempe ratures) . A so lenoid, ca lled the AI C side of th e system . So, ba sica lly low side Compre ssor Control Va lve, indirectly co ntro ls th e press ure and th e AI C Compressor Contro l va lve position of the swash pl ate . Lets see how this co nt rol th e pressure in the case and t he position is done . of the swas h plate, and ulti mately th e out put of The AI C Compressor Co ntro l valve has a pre- the comp ressor. pressurized diaphragm mounted in side t he valve Some com pressors still use a compressor at just below 30psi. Thi s valve is connected to clutc h. The clutc h is mounted behi nd the pu lley. the intake, or low pressure side of the compres- This is sti ll necessary to engage and disengage sor. If the low side fa ll s below diap hragm pres- the co mpressor and is still a potential fa ul t, but sure, the AIC Com presso r Contro l va lve is co nve ntional diagnosti cs preva il here. Check th e commanded for a low openin g and ca n be as low amp draw of the clutc h, and li sten for noisy as 2% (A/C off positi on) . Yo u can monito r t hi s co mp ressor engageme nt. Th ere is a TSB # P-B- manua ll y with a DMM, or thro ugh your sca n too l. 83.55/87 that informs us how to bypass the Th is valve position allows hi gh side pressure into compresso r with a sma ller serpentine belt. If the th e compressor case. The pressure pushes th e noise goes away th ere is a problem with the AIC swash plate in, thereby red ucin g piston stroke pul ley bearin g. Yo u ca n replace the front clutch 1 StarTuned 6
  16. 16. The AIC Compressor Control valve is On vehicles with this compressor pulley,pictured here as component # I . This you will definitely have on AICvalve controls the pressure applied to Compressor Control valve to tum thethe case of the AIC compressor. compressor on and off. If theOn vehicles without on AIC clutch, compressor seizes, the outer pulleythis is how the compressor is turned separates from the inner pulley, thuson and off. saving the belt.and bea ring assembly in the veh icle, so you do simple. On singl e clim ate zone systems with thenot have to remove the compressor. Th ats a ign iti on key on, you set the temperature to " LO"relief since this compressor is one of the harder and within 20 seconds apply the "REST" andones to R& R. A/C compressors that do not use defrost buttons at the same time. Th e LED in thea compressor clutch use a rubber couplin g. rec ircu lation button will flash and the liquid crysta l display shou ld show "diA". Now press the "AUTO" button and a code will be displayed ifSelf-Diagnostics? one has been set. Push the "AUTO" button again and you will adva nce to the next code. Apply the Not only has Mercedes-Benz incorporated a "AUTO" button aga in until the codes start toself-diagnostic function into its AAC systems, but repeat. To clear the codes, use the tempe ratureyou do not need a scan tool to access them . arrow up and arrow down button simultaneouslyTh e contro l panel of the AAC system is the and hold them down for more than five seconds.technici an interface. This rule applies from the In the event that you do not want to erase theearly 90s into the late 90s. Otherwise, Star codes, you can apply the "AUTO" button and theDiagnosis, or its equiva lent will be required . If faults will not be cleared. Shutting the key off willyo u are between these years, the process is end se lf-diagnostics . (Continued on page 20) StarTuned 17
  17. 17. Replace - We replace more parts than aftermarket brands.Engineered - Designed to meet original OEM drawings.Manufactured - Made with same DE components as factory parts.Assembled - Completely assembled from components and not just repaired . Improved Technician Efficiency
  18. 18. 260E 1987-1989 300CE 1988-1993 INTRODUCING: NEW APPLICATIONS 300EITE 1986-1993 3005E1 5EL 1988-1991 3005L 1990-1993 PART NUMBER MODELS YEARA 0002300511 80 35050 1991 C240/C320/S430 35050L 1990-1991 AOOO 230 91 11 80 S500/CL500/CLK320 2004 E320 1994-1995 5L320 1994-1997 E320/E500 2003·2006 5L600 1996-1997 A001 2301211 80 CLS500 2006~ 400El500E 1992-1993 5005L 1990-1993 ML350/ML500/ML55AMG 2003~A 00023006 11 80 E420 1994-1995 A001 23028 11 80 E500 1994 G500/G55 2003+ 5L500 1994-1999 A001 230 68 11 80 ML320/ML430 UP TO 2000 1900 1986-1989 1900T/3000TI TOT 1987 S55AMG/CL55AMG 2003-2005 190E 1985-1993 AOOO 230 90 11 80 C240/C320 UPTO 2003 260E 1987-1989 300CE 1988-1989 CLK320 2003A 000 230 1111 80 3000 1987-1993 300E 1986-1992 AOOO 230 78 11 80 C32AMG KOMPRESSOR 2002-2004 300SE 1988-1992 300SEUTE 1988-1991 C230K M271 E3000 1995 AOOO 230 97 11 80 (VIN RANGE SPECIFIC) 2004 C2201 C280 1994-1995 S600/CL600 2001+A 000230 1311 80 C36AMG 1995 A001 2300111 80 S65AMG/CL65AMG 2005+ 300S0 1992-1993 E55AMG 2004-2006 300SEI 600SEC 1993 600SEL 1992-1993 CLS55AMG 2006A 000230171180 5320/53500 1994-1995 5420 1997-1999 A001 2301411 80 E350/E5S0 2007 S600 1994-1996 CLS550 2007 CL600 1998-1999 5320 1995-1999 E320CDI 2005-2006A 000230 2211 80 S3500 1995 CLK550 2007 S600 1996-1999 CLK55AMG 2003+ 1900 1986-1989 1900T/30001 OTI TDT 1987 A001 23019 11 80 SLK55AMG 2005~ 190E 1985-1993 260E 1987-1989 C55AMG 2005+A 0002302411 80 300CE 1988-1989 300E 1986-1992 2004 300SE 1988-1992 30050L 1986-1987 300SEUTE 1988-1991 4205EU 5605ECI 5EL 1986-1991A 0002302511 80 5605L 1986-1989 400SE 1992 4005EU 5005EC 1993A 119 230 00 11 80 500SEL 1992-1993 5420/500 1994-1995 C280/C43 AMG 19911-2000 CLK320 19911-2003 CLK430 1999-2003 CLK55 AMG/ML320 2001-2002A 00023070 11 80 E320 19911-2002 E430/E55 AMG 2000-2002 ML430 199~2001 ML55AMG 2000 5LK230/5LK320 2001-2004 CL500 2001-2003 CL55AMG 2001-2002A 001 230 0211 80 5430 2002-2003 5500 2002-2003 S55AMG 2002-2003
  19. 19. On dual zone systems, it is sl ightl y different. Here is a Duo-Valve assembly for dualWith the key on make su re the drivers sid e tem-perature is set to " HI" and th e passenger side is zone climate control systems. Thisset to "LO". Within 20 seconds press th e "REST" valve is normally open (defaults to fulland "EC" buttons together and hold them downfor over five seconds. The display will indicate heat if there is a failure) and the AAC"d i R", the LED in the recircu lation button will control unit grounds it to close it dur-blink and once again pressing the "AU TO" buttonon the passenger side wi ll advance you through ing AIC operation. Make sure theseany stored trouble codes. The letter "E" is dis- valves are closing when AIC isplayed on the left side of the LCD and the codeon the right. Hitting the "AUTO" and the arrow requested.button to increase fan speed for two seconds willclear the codes and "FF" wi ll be displayed on the temperature sensors should change their signa lscreen. Pressing the "AUTO" button at this point vo ltage when different temperatures are selectedalso cance ls the code clear. Shutting the ign ition and the system is working properly.switch off ends the process. Outside The Box Self diagnostics are always avai lable to the StarDiagnosis unit, or its aftermarket equiva lent. With One quick note as we close: Not all low A/CStar Diagnosis, not only wi ll you be able to pu ll outputs are caused by the refrigerant system.and clear codes, but you wi ll also be able to acti- Mercedes-Benz uses electric heater contro lvate output controls such as the A/C compressor valves to supply hot coo lant to its heater cores.clutch, mode door contro l, and monitor signa l These va lves de-energized are open. Thi s way ifvoltages in the data stream. This information can there is a failure in the system, you wi ll sti ll havesave hours of diagnostic time on dual and multi- full heat. If these valves do not clo se whenple zone systems like Thermotronic. An exce ll ent commanded, they sti ll allow hot coolant into theway to take advantage of the data-stream is to core. This can increase the temperature in themonitor temperature sensor inputs and open ing cab in to a noticeable degree. Always make surepercentages of mode door outputs. Mode doors the heater contro l va lves are closing properlymove from 0% to 100%. This shou ld indi cate to when the A/C isnt as co ld as your customersyou if a motor is binding or stuck. Th e would li ke it to be.20 StarTuned
  20. 20. A MerGedes-Beuz should be Ime 10 lis origins. So lueu 10 Ihe MefGedes-Benz Classic: CcmtP.l" for GP.nllinc: MC:ITc:cn~ IlP.n:;: Classic Parts. mrpnr~ have: nCCI$!l to owr 40,000 tntP. fitting Gc:nllinr. Clnssic. Pnrts of the: highest qnality. pIlls a 12 month lituiled warranly. They sell dlreGI, ship direGI aud even asslsl In paris speclClGaUon. Mercedes-Benz Classic Center When you waul aulhenUG pariS, ouly Ihe SOUfGe wIll do. MBUSA,com/ClassleCenter To speak with our Parts Experts, call our Parts Order Desk at 1-866-MB-ClASSIC (1-866-622-5277). Mercedes-Benz Classic Center USA, 9 Whatney, Irvine, CA 92618(..1/1 or tor r:r1tiiTion<11dNnil:; <"Ind r, (;(IPY ot rhl~ I imiTcd fJ~m ;,,> Wnrrrliity. (<:l)(lOB Mcr(;r:dr.:;: Ih~n7 USA, II C
  21. 21. Cushioning the BlowAs always, at Mercedes-Benz the top priority is the safety ofthe people who drive its vehicles. Airbag systems need to bemaintained and serviced to ensure the same level of safetythat the engineers intended.22 StarTuned
  22. 22. Mercedes-Benz has always been at the deployment, particularly as relating to childrenforefront of occupancy safety. In 1969, United and smaller passengers.States Federa l law mandated automatic Supplemental Restraint Systems (SRS)occupant restraint systems . Yet, since 1967 have come a long way since the earlyMerced es-Benz had been developing airbag generations. Complex computer algorithmstechnology for its passenger vehicles . By 1980, differentiate between smaller and larger impacts,the company had started to employ this seat occupancy detection sensors prevent airbagadvanced technology on a growing number of its deployment if a light-weight individual (child) isvehicles. Initially, there were some of the same sitting in that seat, and dual/multiple-stageconcerns that we hear about today, such as how airbags have been only a few of the advance-to prevent secondary injury as a result of airbag ments made over the years. D j " i ... ~ I) -g ~ OI!llOOlI!)ldaD 111:.ia~ IU>Q-<lOOlOIThis is a passenger seat occupant sensor and BabySmart™ transceiver for an older SRS(later Occupant Classification Systems have their sensors sealed into the seat cushion).These monitor if someone is sitting in the seat and the relative size of the individual.Regardless, Mercedes-Benz highly recommends that all children be seated in the rearpassenger seats where they are safest. StarTuned 23
  23. 23. COLLISION REPAI R I AIR BAGS determined that there is a fau lt in the system.What is the Goal? There are many DTC (Diagnostic Trouble Codes) associated with SRS . It is your j ob to determine While it is often believed that airbags are what code is setting and what testi ng procedures deployed to counter forward impact in the event need to be implemented. Your Star Diagnosis, or of an accident, this is not entirely true. If a body Compact III , can pull these codes for you and flying forward is struck by a deploying airbag even he lp you step-by-step alo ng a diagnostic traveling in the opposite direction, the impact trouble tree with the use of WIS. might be twice as great, possib ly causing greater When pulling codes from the SRS, you wil l body trauma. The goal of an airbag system is to notice that there are "B" codes. As you may dep loy fully before body contact and gradually know, the Society of Automotive Engineers (SAE) slow down the body t hat is traveling forward. imp lemented a program to homologa te automo-This gradua l slowing process keeps points of tive service information among the various manu-impact at a level the huma n body can absorb. facturers that sell vehic les in the Un ited States.This also means the bag must fully inflate qu ick- You shou ld also know that when search ing fo rly, to the tune of about 40 milliseconds or less. A diagnostic information either in the vehicle itself,body not seat-belted in could impact the bag at or in service information, that DTCs have beenthe wrong time and/or slide around the bag broken down into several categories, such as:negating its intended purpose. Seat belts need tobe used to control the occupants position and • PXXXX Powertrainmaxim ize the air bags effectiveness. In fact, • BXXXX Bodysome older systems were engineered to on ly • CXXXX Chassisrespond with the respective seat belt fastened . • UXXXX Communication With different body types, both the distanceto the airbag (seating position) and energy of • Etc . himpact differ. These facto rs also play into the Since the SRS is part of the body, you willSRSs effectiveness. So, mUlti-stage airbag find that its DTCs are "B" codes. If you would li kesystems were developed that can differentiate to retrieve codes from the SRS, you need tobetween more and less severe impacts and select "Body." The next pull-down menu shoulddep loy with on ly enough force to counter the display SRS or Airbag. Upon retrievi ng codes youforces exerted on an occupant during the will notice all of these codes are "B" codesaccident. With this added sophistication comes un less you have a communication fau lt. All "U"added diagnostic comp lexity. Self-diagnostic codes are for a fai lure in communication withcapability has been incorporated into each one of the other contro l un its. There are two dif-control unit and is mon itored during each ignition ferent codes available from the SRS, first is t hekey cyc le to ensure that the SRS is functioning "Stored Code" and second is the "Active Code."properly. When t he SRS warning light comes on, The stored code is a problem t hat was detectedthe driver is directed to the "Workshop" to using the SRS control un its fai lure criteria, but isaddress the problem. Th is not only serves as a not currently a failure. These problems still needwarning to get the vehicle repaired, but also as a to be addressed, but conventional diagnosticswarning that the SRS may not function properly will probab ly yie ld no failed components at thisin the event of an accident. time. Intermittent electrica l connections and/ or system voltage issues cou ld flag this type of"Visit the Workshop" code. Diagnostic testing should include more in-depth procedures such as voltage drop to If this warning message appears in the dri- arrive at any useful conc lu sion. The active codesvers information display, or after a four- to 20- are just that, active . Th ey are hard faults and aresecond bulb check the Airbag or SRS warning occurring at that moment. Here, straightforwardlight stays on, the SRS se lf-diagnostics have diagnostics shou ld find the cause of the DTC.24 StarTuned
  24. 24. you wi ll now see a pull-down menu of the various sections. Select Volume 5.1 and on the right side of the page you wil l see another list of chassis to choose from. Once you se lect a chassis within a model production year (under se lection 16), there will be displayed an additiona l list of diagnostic service information to choose from. The li st is broken down into three sections, Diagnosis, Electrical Test Program (ETP), and Control Unit Coding. Diagnosis gives you troub le code tables, data PID actual va lues and a symptom-based trouble tree among some other cho ices. ETP gives you component location and step-by-step trouble tree testing for each circuit in the SRS . Keep in mind, these testing methods are based on being a properly equipped shop with the special service tools, such as factory scan tools and breakout boxes, that al low you to precisely follow the test procedures. Accident DamageYellow connectors and harness tape If the vehicle has been in an accident,indicate that this is airbag system se lf-diagnostics indicate sensor data that can bewiring. This is a two-wire squib for the recal led to help indicate what components needdoor-mounted airbag. If you had a fault to be replaced and what sensors have failed.code for this airbag, you would open Obvious repairs include SRS components thatthis connector and measure resistance have deployed, or have received physicalbetween it and the SRS control unit. damage. You do not have to rep lace the contro l unit, or other parts that were not damaged or Once you have retrieved a DTC, you wi ll deployed, unless otherwise instructed by theneed to look up the proper testing procedures party responsible for repairing the vehiGle, suchfor this / these code(s) . Here is where a paid as an insurance company. Obviously, if an airbagsubscription to can pro- has gone off, its going to need to be replaced.vide manufacturer-specific, accurate and perti- Since the ve hicle is obviously being driven at thenent testing for this particular problem . When t ime of the accident, the drivers side airbag isdealing with vehic le s around the 2000 model going to deploy. Since the airbag is gettingyear, you can look up service information in the replaced, we also recommend replacing the" Launc h Manua ls" selection under Service Info, clock spring. Whats a clock spring?or in WIS-Net. There, you will be asked to se lect Since the steering wheel must turn to directthe chassis of the vehicle you are working on. the veh icle and the drivers sid e airbag is in theOnce you have selected the chassis, look at the steering whee l, a device is needed that al lowsleft side of the screen and you will see a list of the firing charge to make it to the airbag nothe various sections of the service repair manu- matter what position the steering wheel is in.als. At the top of that li st should be "Body and The clock spring performs this task . It has anAcc esso ries" just above "Chassis and electrica l connect ion on the steering columnDrivetra in." Select "Body and Accessories" and side . This is what carries the signa l from the SRS StarTuned 25
  25. 25. COLLISION REPAIR / AIR BAGS th at first. If the code does not come back right away, simply turn the steering whee l and see if the code returns. If it does, yo u can now be more certa in that the clock spring has failed, narrowing your search for the solution to the code . Mercedes-Benz recommends that you remove the airbag from the steering wheel and insert a fixed resistance between the two termi- nals in place of the airbag. Then, measure resist- ance from either the steering co lumn through the clock spring, or from the SRS contro l unit. At this point yo u can turn the steering wheel and see if the resistance changes. If it does, then you need to replace the clock spring. Used or reconditioned airbags?In the unfortunate event of a collision, Mercedes-Benz does not recommend thethe SRS works so fast the bags are fully in sta llation of salvaged, used or reconditioneddeployed by the time an occupant airbag system components since they canmakes contact with them. strongly compromise the safety features of the ve hicle, leading to an increased injury or evencontro l unit. This side of the clock spring is death risk to the occupants .mounted solidly to the steering column. A flexible Used or reconditioned airbag componentsband of wire is mounted in the clock spring and do not ensure the same safety features as newcarries the current through to the other side. components, due to the following;This side is solid ly mounted to the steeringwheel. It is the flexible band of wiring that main- 1. History of the component is unknowntains the electrical connection while the wheel is (pre-existing damage, remova l orbeing turned, not the brushes you might expect reconditioning processes, etc.)from having seen cruise or radio controls 2. Airbag components are specifical ly developedmounted in the steering wheel. Since the for each ve hicle, working together with othersteering whee l is used every time the ve hicle is safety systems (e.g. safety-belt, sensors, etc.),driven, th is flexible band gets expanded and resulting in the fact that not every airbag isretracted constantly. Although engineers take compatible with every vehicle.every precaution to build a component that willlast, it will eventual ly wear out. Given sufficient 3. During the life-cycle of a model, severaluse, it wil l final ly break and the connection will enhancements may have been introduced (new regulations, new deve lopments, new parts,be lost. This can also happen if mechanical workoutside of the ve hicle is performed. The act of etc. ). Salvaged, used or reconditioned airbagchangi ng a power steering gear can damage the compo nents do not ensure the fulfillm ent ofclock spring if precautions are not taken. If the the latest requirements.steering knuck le is not carefully removed (and For all of the above reasons, Daimler AGwe know how hard that can be sometimes) strongly recommends that no sa lvaged, used orexcessive steering shaft movement can be reconditioned airbag component be installed ontransmitted up the steering column and damage any Merced es-8en;z in the interest and safety ofthe clock spri ng. all parties (drivers and vehicles occupants, insur- Another simple diagnostic test is to clear ance companies, repairing workshops liability).the clock spring code. If the code returns right Next time, well/ook at the Emergencyaway you have an open in the "Squib" circuit. Tensioning Device (ETD), further testingThis is more than likely the clock spring, so test and checklists.26 StarTuned
  26. 26. Small Repair, Big Opportunity One of the benefits of owning a Mercedes-Benz Mercedes-Benz has the answer. The Small Repairis the timeless style it exhibits. With bodies and Program was instituted earlier this year to allowinteriors sculpted like artwork, its no wonder their Mercedes-Benz dealers and Mercedes-Benz Certifiedowners take pride in them. Unfortunately, Collision Repair shops to handle minor repair jobs atin the real world things happen . Stones are thrown their facilities without a large investment in time orup from the roadway, careless passengers spill money. This comprehensive system provides thethings, wheels contact curbs, and road grime and tools necessary to repair surface damage to alloysalt attack those nice rims. How are we going to help rims, windshields and interiors by means of easy-to-our appearance-conscious customers? use and conveniently-packaged kits. Sticks and Stones The windshield repair kit has all the components needed to fix cracks and stone chips. Resins are used to seal the glass, and polish takes care of any pitting. All the necessary tools, such as syringes and drill bits, are included to complete the job. Keep in mind that this kit is only intended to repair minor problems outside of the drivers field of vision, and are not meant to take care of a problem that has failed a state safety inspection program. Wheels No part of the vehicle is more noticeable than those alloy rims. Unfortunately, even the most stunning wheels are bound to be damaged. The rim repair kit comprises cleaners, fillers, activators and the tools to apply them. An array of colors allows you to color-match the surface of the rim and provide a finish just like a new rim at only a fractio n of the cost. Inside Job The interior repair kit is extensive. Its designed to hand le blemishes in the vehicles interior paneling and upholstery. It can even go so far as to repair exterior plastic components such as the bumper. Fillers, reinforce- ment material and applicators are only some of the materials supplied. Included in the kit are color-matching compounds that will blend in with the original colors and textures of the interior. Hard and soft plastics can be repaired along with leather and vinyl. Teamwork Mercedes-Benz has teamed up with Reliable Automotive Equipment to provide these kits to you. They amount to a cost-effective solution for small repair jobs that will restore the finish that every Mercedes-Benz deserves. To further support this small repair program, Reliable Automotive Equipment includes a training DVD with each kit, and peer-to-peer training is also available. To order these kits, contact your local authorized Mercedes-Benz dealer.28 StarTuned
  27. 27. · Should the gpllg·get .g littl~{o-qgb _· - ..~~ . - - - • - .. • - - - I -- : _ ~" , ~. ~~. - - .:. " - -.__ ~ ~,:- ~ - -- __ - _.. :._ __ ~ - I -.. ..... _ - . , ...... Small scratches, stone impacts, dents and blemishes - and th e custom ers Mercedes can quickly lose the shine from its exterior. And because that is annoyance enough, we keep the costs for a repa ir as low as poss ible - with Mercedes-Benz Small Repair. Special repair methods mean that small appearance defects vanish in next to no time. It goes without saying th at our kits meet the high, tested Mercedes-Ben z quality standards th at you expect. So if you r customers are driving aro und with a small imperfection, it may be able to be repaired with Mercedes-Benz Small Repair. Small Repair Kits are availab le from yo ur authorized Mercedes-Benz dealer. Training on th e Small Repair methods are availabl e from Reliable Automotive Eq uipment. Please contact Reliable Automotive Equipment to inquire about training yo ur staff to perform these repa irs quickly and efficientl y. RAE RELIABLE AUTOMOTIVE EQUIPMENT, INC. 1.800.328.7855
  28. 28. STARTUNEDFACTORY SERVICE BULLETINSWhi ning/High-Pitched WhistleComi ng From Front of EngineAll Light Truck Models Equippedwit h Engine M272 or M273 A whi ning or high-pitched whistlingnoise com ing from the fro nt secti on of t heengine may be caused by a faulty upperidler pu lley. To resolve, rep lace the up peridler pull ey with a new un it. The pul ley issupplied as a package co ntain ing th e Parts Informationmounting bolt, dust cover and space r. Fit Quantity Part Name Part Numberthe spacer between the timing case cover Ti ghtener Pull ey A272 20208 19and guide pulley. 1. Remove doo r li nin g. Refer to WIS documentKnocking N oise in Rear Door AR72 .12-P-101OGZ (164) orWhen Operating Power Window AR72. 12-P-101 0RT (251).Model I 64. I 22/ I 72/175/ 177 2. Remove doo r mod ul e. Refer to WIS document AR 72. 12-P-010 3GZ (1 64) or186/822/87 1 /886, AR 72. 12-P-0103 RT (251).up to VIN A258996, 3. Remove broken limit stop from door.Model 25 1.1 22/156/ I 65/175/177, 4. In sta ll new li mit stop (Figure 1).up t o VIN A058266 5. Reinstall doo r mod ule. Refer to WIS document AR72. 12-P-010 3GZ (164) or AR72. 12-P-0103RT (251). 6. Rein sta ll doo r lining. Refer to WIS document AR 72. 12-P-101OGZ (1 64) or AR72. 12-P-101 0RT (251). 7. Renorm alize power wind ows . A knock ing noise that occ urs when th e powe r Parts Informationwindow is operated downwa rd and reac hes the lower Quantity Pa rt Name Part Numberlimit position may be caused by a broken plasti c li mit Li mit Stop A164 73000 28sto p. To remedy, perform the fo ll owing.30 StarTuned
  29. 29. STARTUNEDGENUINE MERCEDES-BENZ PARTS ... NEARBY Belmont Palo Alto Walnut CreekAlabama Autobahn Motors Park Avenue Motors Mercedes-Benz of Walnut Creek 650-637-2333 650-494-0311 925-937-1655DothanMike Schmitz Automotive Beverly Hills Pasadena West Covina334-794-6716 Mercedes-Benz of Beverly Hills Rusnak/ Arcadia Mercedes-Benz of West Covina 310-659-2980 626-795-8004 626-859-1200Hoover Buena Park PleasantonCrown Automobile Colorado House of Imports Mercedes-Benz of Pleasanton205-985-4200 714-562-1100 925-463-2525 Colorado SpringsHuntsville Calabasas Riverside Mercedes-Benz of Colorado SpringsMercedes-Benz of Huntsville Mercedes-Benz of Calabasas Walters Auto Sales & Service, Inc. 719-575-7950256-837-5752 818-591 -2377 951-688-3332 Denver Carlsbad Rocklin Murray Motor ImportsMobile Von Housens Motors Hoehn Motors 303-759-3400McConnell Automotive 916-630-8877 760-438-4454251-476-4141 Chico Sacramento LittletonMontgomery Courtesy Motors Auto Center Mercedes-Benz of Sacramento Mercedes-Benz of LittletonJack Ingram Motors 530-893-1300 916-924-8000 303-738-7700334-277-5700 San Diego EI Dorado Hills Westminster Mercedes-Benz of Eldorado Hills Mercedes-Benz of San Diego Mercedes-Benz of WestminsterTuscaloosa 916-567-5100 858-279-7202Leigh Automotive 303-410-7800205-556-1111 Encino San Francisco Mercedes-Benz of Encino Mercedes-Benz of San Francisco ConnecticutAlaska 818-788-0234 415-673-2000 San Jose DanburyAnchorage Escondido Beshoff Motorcars Mercedes-Benz of DanburyMercedes-Benz of Anchorage Mercedes-Benz of Escondido 408-239-2300 203-778-6333907-277-3383 760-745-5000Fairbanks Fremont San Jose FairfieldAuto Service Company Fletcher Jones Motor Cars Smythe European Mercedes-Benz of Fairfield907-456-6217 510-623-1111 408-983-5200 203-368-6725Arizona Fresno San Luis Obispo Greenwich Mercedes-Benz of Fresno Kimball Motor Mercedes-Benz of GreenwichChandler 559-438-0300 805-543-5752 203-869-2850Mercedes-Benz of Chandler San Rafael Glendale Hartford480-403-3400 R.A.B. Motors Calstar Motors New Country Motor CarsPhoenix 818-246-1800 415-454-0582 860-278-2000Phoenix Motor Santa Barbara602-264-4791 Laguna Niguel Mercedes-Benz of Laguna Niguel Santa Barbara Auto Group New London 949-347-3700 805-682-2000 Carriage House of New LondonPhoenix 860-447-3361Schumacher European Santa Clarita480-991-1155 La Jolla Heinz Gietz Autohaus Mercedes-Benz of Valencia North HavenTucson 858-454-7137 661-753-5555 Mercedes-Benz of North HavenMercedes-Benz of Tucson 203-239-1313 Los Angeles Santa Monica520-886-1311 W.I. Simonson Downtown L.A. Motors Delaware 213-748-8951 310-526-4700Arkansas Santa Rosa Milford Manhattan BeachFayetteville Carwell Smothers European I.G. BurtonMercedes-Benz of Northwest Arkansas 310-303-3500 707-542-4810 302-424-3042479-521-7281 Modesto Signal Hill Wilmington Modesto European Mercedes-Benz of Long Beach Mercedes-Benz of WilmingtonLittle Rock 209-522-8100Riverside Motors 562-988-8300 302-995-2211501-666-9457 Monterey Stockton Mercedes-Benz of Monterey Berberian European Motors FloridaCalifornia 831-375-2456 209-944-55 11 ClearwaterAnaheim Newport Beach Thousand Oaks Lokey MotorMercedes-Benz of Anaheim Fletcher Jones Motor Cars Silver Star A.G. 727-530-1661714-777-1 900 949-718-3000 805-371-5400 Oakland Coral GablesArcadia Tonrance Mercedes-Benz of Oakland Mercedes-Benz of Coral GablesRusnak/ Arcadia Mercedes-Benz of South Bay 510-832-6030 305-445-8593626-447-1117 310-534-3333Bakersfield Palm Springs Van Nuys Cutler BayMercedes-Benz of Bakersfield Mercedes-Benz of Palm Springs Keyes European Mercedes-Benz of Cutler Bay661-836-3737 760-328-6525 818-461-3900 305-251-0345 StarTuned 3 1