Komatsu wa250 6 wheel loader service repair manual (sn 76001 and up)

CEBM000703
Shop
Manual
WA250-6
WHEEL LOADER
SERIAL NUMBERS WA250-6 A76001 and up
ENGINE 6D107E-1
This material is proprietary to Komatsu America Corp. and is not to be reproduced, used, or disclosed except in
accordance with written authorization from Komatsu America Corp.
It is our policy to improve our products whenever it is possible and practical to do so. We reserve the right to
make changes or improvements at any time without incurring any obligation to install such changes on products
sold previously.
Due to this continuous program of research and development, revisions may be made to this publication. It is
recommended that customers contact their distributor for information on the latest revision.
Copyright 2010 Komatsu
Printed in U.S.A.
Komatsu America Corp.
January 2010

FOREWORD CONTENTS
00-2 d WA250-6
CONTENTS 00
01 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01-1
10 STRUCTURE, FUNCTION AND MAINTENANCE STANDARD . . . . . . . . . . . . . . . . . . . . 10-1
20 STANDARD VALUE TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1
30 TESTING AND ADJUSTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1
40 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40-1
50 DISASSEMBLY AND ASSEMBLY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-1
90 DIAGRAMS AND SCHEMATICS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90-1

FOREWORD SAFETY
WA250-6 00-3 ➁
SAFETY 00
Safety Notice 00
General Precautions 00
Mistakes in operation are extremely dangerous. Read the
Operation & Maintenance Manual carefully BEFORE
operating the machine. In addition, read this manual and
understand its contents before starting the work.
1. Before carrying out any greasing or repairs, read all the
precautions given on the labels which are fixed to the
machine. For the locations of the safety labels and a
detailed explanation of precautions, see the Operation &
Maintenance Manual.
2. When carrying out any operation, always wear safety
shoes and helmet. Do not wear loose work clothes, or
clothes with buttons missing.
• Always wear safety glasses when hitting parts with
a hammer.
• Always wear safety glasses when grinding parts
with a grinder, etc.
3. If welding repairs are needed, always have a trained,
experienced welder carry out the work. When carrying
out welding work, always wear welding gloves, apron,
shielding goggles, cap, and other clothes suited for
welding work.
4. When carrying out any operation with two or more
workers, always agree on the operating procedure
before starting. Always inform your fellow workers
before starting any step of the operation. Before starting
work, hang UNDER REPAIR signs on the controls in
the operator's compartment.
5. Keep all tools in good condition; learn the correct way
to use them; and use the proper ones. Before starting
work, thoroughly check the tools, machine, forklift,
service car, etc.
6. Only qualified workers must carry out work and
operations which require license or qualification.
7. Decide a place in the repair workshop to keep tools and
removed parts. Always keep the tools and parts in their
correct places. Always keep the work area clean and
make sure that there is no dirt or oil on the floor. Smoke
only in the areas provided for smoking. Never smoke
while working.
8. Avoid continuing work for long hours and take rests at
proper intervals to keep your body in good condition.
Take rests in specified safe places.
Safety Points
Important Safety Notice 00
Proper service and repair is extremely important for the safe operation of your machine. The service and repair techniques
recommended and described in this manual are both effective and safe methods of operation. Some of these operations
require the use of tools specially designed for the purpose.
To prevent injury to workers, the symbols and are used to mark safety precautions in this manual. The cautions
accompanying these symbols should always be followed carefully. If any dangerous situation arises or may possibly arise,
first consider safety, and take the necessary actions to deal with the situation.
WARNING! Never modify, weld, cut, or drill
on any part of a ROPS
structure. Doing so may
weaken the structure which
could lead to possible failure in
a rollover situation
1 Good arrangement
2 Correct work clothes
3 Following work standard
4 Making and checking signs
5
Prohibition of operation and handling by
unlicensed workers
6 Safety check before starting work
7
Wearing protective goggles
(for cleaning or grinding work)
8
Wearing shielding goggles and protectors
(for welding work)
9 Good physical condition and preparation
10
Precautions against work which you are not
used to or work with which you are too
familiar

FOREWORD SAFETY
00-4 ➁
Preparations for Work 00
1. Before adding oil or making repairs, park the machine
on hard, level ground, and block the wheels or tracks to
prevent the machine from moving.
2. Before starting work, lower blade, ripper, bucket, or any
other work equipment to the ground. If this is not
possible, insert the safety pin or use blocks to prevent
the work equipment from falling. In addition, be sure to
lock all the control levers and hang warning signs on
them.
3. When disassembling or assembling, support the
machine with blocks, jacks, or stands before starting
work.
4. Remove all mud and oil from the steps or other places
used to get on and off the machine. Always use the
handrails, ladders, or steps when getting on or off the
machine. Never jump on or off the machine. If it is
impossible to use the handrails, ladders, or steps, use a
stand to provide safe footing.
Precautions During Work 00
1. When removing the oil filler cap, drain plug, or
hydraulic pressure measuring plugs, loosen them slowly
to prevent the oil from spurting out. Before
disconnecting or removing components of the oil, water,
or air circuits, first release the pressure completely from
the circuit.
2. The coolant and oil in the circuits are hot when the
engine is stopped; be careful not to get burned. Wait for
the oil and coolant to cool before carrying out any work
on the oil or water circuits.
3. Before starting work, remove the leads from the battery.
ALWAYS remove the lead from the negative (-)
terminal first.
4. When raising heavy components (in excess of 25 kg
(55 lb)), use a hoist or crane. Check that the wire rope,
chains, and hooks are free from damage. Always use
lifting equipment which has ample capacity. Install the
lifting equipment at the correct places. Use a hoist or
crane and operate slowly to prevent the component from
hitting any other part. Do not work with any part still
raised by the hoist or crane.
5. When removing a cover which is under internal pressure
or under pressure from a spring, always leave two bolts
in position on opposite sides. Loosen the bolts gradually
and alternately to release the pressure, and then remove
the cover.
6. When removing components, be careful not to break or
damage the wiring, Damaged wiring may cause
electrical fires.
7. When removing piping, stop the fuel or oil from spilling
out. If any fuel or oil drips on the floor, wipe it up
immediately. Fuel or oil on the floor can cause you to
slip, or can even start fires.
8. Gasoline or other fuels should never be used to clean
parts. Clean parts with appropriate solvents.
9. Be sure to assemble all parts again in their original
places. Replace any damaged parts or parts that must not
be reused with new parts.
• When installing hoses and wires, be sure that they
will not be damaged by contact with other parts
when the machine is being operated.
10. When installing high pressure hoses, make sure that
they are not twisted. Damaged tubes are dangerous, so
be extremely careful when installing tubes for high
pressure circuits. Also check that connecting parts are
correctly installed.
11. When assembling or installing parts, always use the
specified tightening torques. When installing protective
parts such as guards, or parts which vibrate violently or
rotate at high speed, be particularly careful to check that
they are installed correctly.
12. When aligning two holes, never insert your fingers or
hand. Be careful not to get your fingers caught in a hole.
13. When measuring hydraulic pressure, check that the
measuring tool is correctly assembled before taking any
measurements.
14. Take care when removing or installing the tracks of
track-type machines. When removing the track, the
track separates suddenly; never let anyone stand at
either end of the track.
15. When jump-starting the machine, only use a machine of
similar size and voltage. Never use an arc welder or
other electrical generating equipment to jump-start the
machine. Carefully review the safety procedures for
jump starting the machine.
16. Before starting work, stop the engine. When working on
or around a rotating part, stop the engine. When
checking the machine without stopping the engine
(measuring oil pressure, revolving speed, temperature,
etc.), be extremely careful not to get rolled or caught in
rotating or moving parts.
17. If the engine is operated for a long time in a place which
is not ventilated well, you may suffer from gas
poisoning. Before starting the engine, open the windows
and doors so that the area is well ventilated.

DISASSEMBLY AND ASSEMBLY ENGINE AND COOLING SYSTEM
50-32 C WA250-6
ENGINE AND COOLING SYSTEM
Fuel Supply Pump
Removal
1. Open and fix right engine side cover (1).
★ Check that the cover is locked securely.
2. Remove fuel prefilter and bracket assembly (2).
★ Use ropes to fix fuel prefilter and bracket assembly (2) to the
machine.
3. Disconnect wiring harness connector CN-CP3 (3) from fuel supply
pump (4).
4. Disconnect fuel filter hoses (5) and (6) from fuel supply pump (4).
5. Disconnect fuel return hose (7) from fuel supply pump (4).
★ If there is mud stuck to the components, lock (L) may become
stiff. Clean the connecting area.
★ Press lock (L) from both sides and pull out hose (5).
★ Plug the disconnected hose to prevent fuel leakage.
WARNING! Stop the machine on level ground and set the lock bar to the frame to lock the front and rear
frames.
WARNING! Lower the work equipment to the ground; stop the engine; apply the parking brake; and put chocks
under the tires.
WARNING! Disconnect the cable from the negative (-) battery terminal.

WA250-6 50-33 C
6. Disconnect fuel supply hose (8) from fuel supply pump (4). [*1]
7. Remove the two clamps of boot (9) and fuel high-pressure
pipe (10).
8. Disconnect fuel high-pressure pipe (10) from fuel supply
pump (4). [*2]
★ Remove the boot on the common rail side of high-pressure
pipe (10) and loosen the sleeve nut.
9. Remove three mounting nuts at part (A) and fuel supply pump
assembly (11). [*3]
★ Remove fuel supply pump assembly (11) and the gear as a
unit. The gear does not have a positioning mark (missing
tooth), etc.

50-34 C WA250-6
Installation
• Carry out installation in the reverse order of removal.
★ The internal parts of the fuel hose adapter may be damaged when it is removed. Do not reuse the fuel hose; use a new
one when assembling.
[*1]
[*2]
Installing high-pressure pipe (10)
1. Use your fingers to tighten the sleeve nut.
2. Check that the high-pressure pipe is installed correctly and tighten the sleeve nut to the following torque.
3. Install boot (9).
★ Direct the slit of the boot down.
★ The boot is installed so that fuel does not spout over the hot
parts of the engine and catch fire if there is a leak for any
reason.
[*3]
★ If too much grease is applied to O-ring (13), it will ooze out. Do
not apply excessive grease. (Apply grease to the O-ring groove
area of part (B).)
★ When installing new fuel supply pump mounting stud bolts (14) to
replace the existing ones, apply Loctite (LT-2) to the bolts.
4. Install fuel supply pump (12).
• Bleeding air
Bleed air from the fuel system. For details, see FUEL SYSTEM:
Bleeding Air from Fuel Circuit in the Testing and Adjusting section.
Joint bolt: 19.6 – 29.4 N•m (15 – 22 lbf ft)
Sleeve nut: 35 ±3.5 N•m (26 ±3 lbf ft)
WARNING! Be sure to use the genuine fuel high-pressure pipe clamp and strictly observe the specified torque.
Fuel supply pump mounting nut: 24 ±4 N•m (18 ±3 lbf ft)

WA250-6 50-35 C
Fuel Injector
Special Tools
Removal
1. Loosen the radiator cap to drain the coolant.
2. Remove the engine hood. For details, see Engine Hood (removal
procedure) in this section.
3. Lift off muffler (1).
★ Be careful that the muffler does not interfere with water drain
tube (2).
Symbol Part No. Part Name
Necessity
Qty
New/Remodel
Sketch
A
3 795-799-6700 Puller ■ 1
4 795-799-1131 Gear ■ 1
5 795-799-8150 Remover ● 1
frames.
Lower the work equipment to the ground; stop the engine; apply the parking brake; and put chocks
under the tires.
Disconnect the cable from the negative (-) battery terminal.
If the radiator coolant temperature is high, you may scald yourself with the hot coolant. Wait until
the coolant cools down then drain the coolant.
Radiator: Approximately 22 l (5.8 gal)
Muffler: Approximately 35 kg (77 lb)

50-36 C WA250-6
4. Disconnect engine intake air heater wiring harness terminal
CN-E07B (3). [*1]
5. Remove clamp (4) and bracket (4a). [*2]
6. Remove clamp (5), air hose (5a), mounting bolt (6a), and intake air
inlet elbow (6). [*3]
★ Remove the engine intake air heater also.
7. Remove two wiring harness clamps (7).
8. Disconnect wiring harness connector (8).
★ While pressing the lock of wiring harness connector (8) with a
flat-head screwdriver [1], pull the connector in the direction of
the arrow.
★ Do not remove the fuel pressure sensor (PS) except if you are
replacing it.
9. Disconnect three wiring harness connectors (9). [*4]
★ While pressing the lock of the wiring harness connector with a
flat-head screwdriver [2], pull the connector.
★ Move wiring harness (10) toward the intake manifold.

WA250-6 50-37 C
10. Using hexagonal wrench (width across flats: 3 mm), remove blow-
by duct (11). [*5]
11. Remove six mounting nuts (12) and cylinder head cover (13).
[*6]
12. Remove six boots (14). [*7]
13. Remove six high-pressure pipes (15). [*8]
★ Loosen the sleeve nut on the common rail side of each high-
pressure pipe.
14. Position the crankshaft according to the following procedure.
A. Remove plug (16) under the starting motor and set tool A4.
B. Rotate the crankshaft forward (counterclockwise viewing
from the flywheel side) to set marks (M1) and (M2).
Mark (M1): Top of projection of front cover
Mark (M2): A wide slit on slitted revolution sensor disc at rear
of crankshaft pulley
Mark (M3): Yellow paint on vibration damper (on
prolongation of wide slit (M2))
★ Set the projection top of mark (M1) within the wide
slit (M2).
★ There is a yellow paint mark (M3) on the prolongation of
wide slit (M2).
★ When the marks are set as described above, the piston of
the No. 1 or No. 6 cylinder is 76 – 88° before the top dead
center.
★ See ENGINE COMPONENTS: Valve Clearance in the
Testing and Adjusting section.
★ Use tool A4 to rotate the crankshaft.

50-38 C WA250-6
15. Remove the 12 mounting bolts and rocker arm (17).
★ Loosen locknut (18) and then loosen adjustment screw (19) by
two to three turns so that an excessive force is not applied to
the push rod when the rocker arm is installed.
16. Remove 12 cross-heads (20).
★ Record the installed positions and the shapes of holes (a) and
(b) of the cross-heads. (When assembling, reinstall each
cross-head in the same direction.)
17. Remove retaining nuts (21) and six inlet connectors (22).
★ Before removing, clean the inlet connectors carefully so that
mud, etc. stuck around them does not enter the connector
holes.
★ Tool A5 is used for removal of inlet connector (22). (See the
Special Tools list.)

WA250-6 50-39 C
18. Remove two wiring harness mounting nuts (24) from fuel
injector (23).
19. Remove two mounting bolts (25) of fuel injector (23).
20. Using tool A3, remove fuel injector (23).
★ Be careful that dirt and foreign matter do not enter the fuel
injector area.
Wiring Harness Color Cylinder No.
White 1, 3, 5
Black 2, 4, 6

50-40 C WA250-6
Installation
★ The internal parts of the fuel hose adapter may be damaged when it is removed. Do not reuse the fuel hose; use a new one
when assembling.
When replacing the fuel injector with a new one, be sure to replace the inlet connector with a new one also.
1. Install fuel injector.
★ Check that the fuel injector sleeve (23a) is free from flaws and
dirt.
A. Fit O-ring (26) and gasket (27) to fuel injector (23).
B. Apply engine oil to O-ring (26) of fuel injector (23) and the
mounting hole on the cylinder head side.
★ See Fuel, Coolant, and Lubricants in the General section.
C. While setting convex and concave parts (A), install
holder (28) to fuel injector (23).
D. Insert fuel injector (23) in the cylinder head, directing its fuel
inlet hole toward the air intake manifold.
E. Tighten two mounting bolts (25) of fuel injector (23) by three
to four turns.
F. Apply engine oil to the mounting hole of inlet connector (22)
on the cylinder head side.
G. Apply engine oil to O-ring (29) of inlet connector (22).
H. Insert inlet connector (22) correctly, while setting part (B) to
the groove on the cylinder head side.

WA250-6 50-41 C
I. Secure inlet connector (22) by tightening retaining nut (21)
lightly.
J. Tighten two mounting bolts (25) of fuel injector (23)
alternately.
K. Tighten retaining nut (21).
L. Install the wiring harnesses to fuel injector (23) and tighten
two mounting nuts (24).
★ Installed positions of wiring harnesses
2. Install inlet connector.
A. Precaution: When replacing the fuel injector with a new one,
be sure to replace the inlet connector also.
B. Check the inlet connector visually. If it has any of the
following faults, replace it.
• There is a burr or a worn part at front end (a) or rear
end (b) of the inlet connector.
• There is foreign matter in the edge filter at rear end (c) of
the inlet connector.
• The O-ring at upper part (d) of the inlet connector is
cracked or deteriorated.
C. Check the inlet connector visually. If it has any of the
following faults, replace it and the fuel injector together.
• There is a worn part or an uneven seat contact mark on
sealing face (e) at the front end of the inlet connector.
★ If high-pressure fuel leaks through the inlet connector, the
seal face has fine streaks or cracks.
Retaining nut (21): 15 ±5 N•m (11 ±4 lbf ft)
Fuel injector mounting bolt (25): 8.0 ±0.8 N•m (71 ±7 lbf in)
Retaining nut (21): 50 ±5 N•m (37 ±4 lbf ft)
Wiring harness mounting nut (24): 1.5 ±0.25 N•m (13 ±2 lbf in)
White 1, 3, 5
Black 2, 4, 6

50-42 C WA250-6
3. Install the cross-head and rocker arm.
★ The shapes of the holes (a) and (b) of each cross-head are
different. When reusing the cross-heads, install each of them
to the same intake/exhaust valve in the same direction as it
was installed.
A. Check that the ball of adjustment screw (19) is set in the push
rod socket securely and then tighten mounting bolts (30).
B. Adjust the valve clearance. For details, see ENGINE
COMPONENTS: Valve Clearance in the Testing and
Adjusting section.
★ Carry out the following installation in the reverse order of
removal.
[*1]
[*2]
[*3]
[*4]
[*5]
Rocker arm mounting bolt (30): 36 ±5 N•m (319 ±44 lbf ft)
Locknut (18): 24 ±4 N•m (18 ±3 lbf ft)
Wiring harness terminal CN-E07B (3): 4.0 ±0.6 N•m (35 ±5 lbf in)
Clamp (4): 10.8 – 26.5 N•m (9 – 20 lbf ft)
Clamp (5): 8.8 ±0.5 N•m (78 ±4 lbf in)
Intake air inlet elbow mounting bolt (6a): 24 ±4 N•m (18 ±3 lbf ft)
WARNING! Install each fuel high-pressure pipe and wiring harness at a distance of at least 10 mm (0.4 in)
from each other.
Blow-by duct mounting bolt: 7 ±2 N•m (62 ±18 lbf in)

WA250-6 50-43 C
[*6]
[*7], [*8]
★ If the taper seal area of the fuel high-pressure pipe has any of the
following defects, replace the fuel high-pressure pipe.
• There is a visible lengthwise slit (b) or spot (c) in range (a) at
2 mm (0.08 in) from the end.
• Taper seal end (d) at 2 mm (0.08 in) from the end has stepped-
type wear which you can feel with your nail.
★ Carry out the following procedure to install the fuel high-pressure
pipes.
1. Temporarily install fuel high-pressure pipes (31) – (36).
2. Tighten fuel high-pressure pipes (31) – (36) in the following order.
A. Tighten the cylinder head side of fuel high-pressure pipes (31)
and (36).
B. Tighten the common rail side of fuel high-pressure pipes (31)
and (36).
C. Tighten the cylinder head side of fuel high-pressure pipes
(32), (33), (34), and (35).
D. Tighten the common rail side of fuel high-pressure pipes (32),
(33), (34), and (35).
3. Install six boots (14) to the fuel high-pressure pipes.
★ Direct the slit of the boot out and down.
★ The boots are installed so that fuel does not spout over the hot parts of the engine and catch fire if there is a leak for
any reason.
Cylinder head cover mounting nut (12): 24 ±4 N•m (18 ±3 lbf ft)
WARNING! Do not bend the fuel high-pressure pipe to correct it before installation.
WARNING! Be sure to use the genuine fuel high-pressure pipe clamps and observe the torque.
Sleeve nut: 0.2 – 0.8 N•m (2 – 7 lbf in)
Sleeve nut: 35 ±3.5 N•m (26 ±3 lbf ft)

50-44 C WA250-6
• Bleeding air
Bleed air from the fuel system. For details, see FUEL SYSTEM: Bleeding Air from Fuel Circuit in the Testing and
Adjusting section.
• Refilling with coolant
Add coolant through the coolant filler to the specified level. Run the engine to circulate the coolant through the system.
Check the coolant level again.
Total amount of coolant: 22 l (5.8 gal)
(For details, see Fuel, Coolant, and Lubricants in the General section.)

WA250-6 50-45 C
Cylinder Head Assembly
Special Tools
Removal
1. Loosen the radiator cap to drain the coolant.
2. Remove the engine hood. For details, see Engine Hood (removal procedure) in this section.
3. Lift off muffler (1).
★ Be careful that the muffler does not interfere with water drain
tube (2).
Symbol Part No. Part Name
Necessity
Qty
New/Remodel
Sketch
A
3 795-799-6700 Puller ■ 1
4 795-799-1131 Gear ■ 1
5 795-799-8150 Remover ● 1
6 790-331-1120 Wrench (angle) ● 1
7 795-790-4510 Gauge ● 1
frames.
WARNING! Lower the work equipment to the ground; stop the engine; apply the parking brake; and put chocks
under the tires.
WARNING! Disconnect the cable from the negative (-) battery terminal.
WARNING! If the radiator coolant temperature is high, you may scald yourself with the hot coolant. Wait until
the coolant cools down then drain the coolant.
Radiator: Approximately 22 l (5.8 gal)
Muffler: Approximately 35 kg (77 lb)

50-46 C WA250-6
4. Disconnect engine intake air heater wiring harness terminal
CN-E07B (3). [*1]
5. Remove clamp (4) and bracket (4a). [*2]
6. Remove clamp (5), air hose (5a), and intake air inlet elbow (6).
★ Remove the engine intake air heater also. [*3]
7. Remove bracket (7).
8. Remove wiring harness clamp (8).
10. Remove air conditioner compressor (10). [*4]
★ Use ropes to fix air conditioner compressor (10) to the
machine.
11. Disconnect fuel filter hoses (11) and (12).
★ If mud is sticking to the components, lock (L) may become
stiff. Clean the connecting area.
★ Press lock (L) from both sides and pull out hose (12).
★ Plug the disconnected hoses to prevent fuel leakage.
12. Disconnect fuel return hose (13).
13. Remove fuel prefilter hose clamp (14).
14. Remove two air conditioner compressor hose clamps (15).
15. Remove fuel filter and bracket (16).

WA250-6 50-47 C
16. Remove two clamps (17).
17. Disconnect engine coolant temperature sensor connector (18).
18. Disconnect ambient air pressure sensor connector (19).
A. Move the lock of ambient air pressure sensor connector (19)
in the direction of the arrow.
B. Pull out the connector while pressing the claw.
19. Disconnect intake air pressure sensor connector (20).
20. Remove two wiring harness clamps (21).
★ While pressing the lock of wiring harness connector (22) with
flat-head screwdriver [1], pull the connector in the direction of
the arrow.
★ Do not remove fuel pressure sensor (PS) except if you are
replacing it.

50-48 C WA250-6
22. Disconnect three wiring harness connectors (23). [*5]
★ While pressing the lock of the wiring harness connector with
flat-head screwdriver [2], pull the connector.
★ Move wiring harness (24) toward the intake manifold.
23. Disconnect fuel drain hose (25). [*6]
24. Disconnect fuel high-pressure pipe (26). [*7]
25. Remove six boots (27). [*8]
26. Remove six high-pressure pipes (28). [*9]
★ Loosen the sleeve nut on the common rail side of each
high-pressure pipe.
27. Disconnect radiator upper hose (29). [*10]
28. Disconnect air aftercooler upper hose (30). [*11]
29. Disconnect heater hose (31).
30. Disconnect corrosion resistor hose (32).
31. Remove corrosion resistor and bracket (33).

WA250-6 50-49 C
32. Remove wiring harness clamp (34).
33. Remove two heat insulation plates (35).
34. Remove heat insulation plate (36).
35. Remove cover (37).
36. Disconnect wiring [1] harness connectors CN-E02 and
CN-E03 (38).

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50-50 C WA250-6
37. Put the wrench in part (A) (width across flats: 12.7 mm) of
tensioner (40) and turn it in the unwinding direction to decrease the
tension of fan belt (41).
38. Remove alternator (39).
39. Disconnect turbocharger lubricating oil inlet tube (42) and drain
hose (43). [*12]
40. Remove the two mounting bolts and bracket (44).
41. Remove the mounting bolts of exhaust manifold (45), leaving
some of them installed. [*13]
42. Temporarily sling exhaust manifold and turbocharger (46) and
remove the remaining mounting bolts.
43. Lift off exhaust manifold and turbocharger (46).
WARNING! Set the wrench securely to the concave
section of tensioner (40) before turning it. (The
spring of tensioner (40) is strong. If the wrench
[1] is set incompletely and turned, it comes off;
that is very dangerous.)
WARNING! After removing belt (41), return tensioner (40)
slowly and carefully.
WARNING! Be careful not to catch your finger between the
pulley and fan belt (41) during work.
Exhaust manifold and turbocharger 45 kg (99 lb)

WA250-6 50-51 C
44. Using hexagonal wrench (width across flats: 3 mm), remove
blow-by duct (47). [*14]
45. Remove six mounting nuts (48) and cylinder head cover (49).
[*15]
46. Position the crankshaft according to the following procedure.
A. Remove plug (50) under the starting motor and set tool A4.
B. Rotate the crankshaft forward (counterclockwise viewing
from the flywheel side) to set marks (M1) and (M2).
Mark (M1): Top of projection of front cover
Mark (M2): A wide slit on slitted revolution sensor disc at rear
of crankshaft pulley
Mark (M3): Yellow paint on vibration damper (on
prolongation of wide slit (M2))
★ Set the projection top of mark (M1) within the wide
slit (M2).
★ There is a yellow paint mark (M3) on the prolongation of
wide slit (M2).
★ When the marks are set as described above, the piston of
the No. 1 or No. 6 cylinder is 76 – 88° before the top dead
center.
★ See ENGINE COMPONENTS: Valve Clearance in the Testing and Adjusting section.
★ Use tool A4 to rotate the crankshaft.
47. Remove the 12 mounting bolts and rocker arm (51).
★ Loosen locknut (52) and then loosen adjustment screw (53) by
two to three turns so that an excessive force is not applied to
the push rod when the rocker arm is installed.

50-52 C WA250-6
48. Remove 12 cross-heads (54).
★ Record the positions and the shapes of holes (a) and (b) of
each cross-head. (When assembling, reinstall each cross-head
in the same direction.)
49. Remove retaining nuts (55) and six inlet connectors (56).
★ Before removing, clean the inlet connectors carefully so that
any mud, etc. stuck around the connectors does not enter the
connector holes.
★ Tool A5 is set for removal of inlet connector (55). (See the
Special Tools list.)
50. Remove two wiring harness mounting nuts (58) from fuel
injector (57).
51. Remove two mounting bolts (59) of fuel injector (57).
White 1, 3, 5
Black 2, 4, 6

Komatsu wa250 6 wheel loader service repair manual (sn 76001 and up)

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Komatsu wa250 6 wheel loader service repair manual (sn 76001 and up)