A bad water pump may leak coolant, fail to circulate it properly, or make grinding noises. This can be caused by rust in the cooling system, a lack of coolant, or overtightened belts. When replacing a water pump, the old gasket material must be scraped off and surfaces cleaned without damaging them. The new pump should be fitted with bolts started by hand and then torqued to specification, using sealer if specified. Other components like the air conditioning compressor and alternator also need reinstalling.