BEFORE installing a new water pump remember the following:
- If the old pump will still circulate coolant through the engine, ALWAYS clean the cooling system with a chemical cleaner and reverse flush all sediment, rust, and scale before removing the old pump. Failure to do so can result in premature seal failure in the new pump due to a dirty system.
- On vehicles equipped with timing belts, care must be taken when removing the water pump so that engine timing is not disturbed, which would result in internal engine damage.
- Clean out any built-up sediment and scale from the impeller cavity in the engine block.
When installing the new pump, remember:
- Do NOT force the pump on by striking the end of the shaft.
- Tighten mounting bolts gradually and evenly in a staggered sequence to the vehicle manufacturer’s torque specifications. Do NOT over torque bolts, which may result in fractures caused by sudden overload.
- It is important to check the condition of the current fan clutch, fan, and fan belt tensioner. If any of these items appear to be worn, damaged, or imbalanced, replace them. Failure to do so can result in early failure or damage to the new pump. See Fig. 1
- Never adjust belts tighter than specified in the factory service manual. Excessive tightening of belts running over the water pump pulley is the major cause of premature bearing failure and breaking of the bearing shaft or housing. See Fig. 2
- On models equipped with automatic belt tensioners, be sure to inspect and test the operation of the tensioner prior to reusing. Most vehicle manufacturers have testing procedures or specifications for these tensioners.
- Turn pump shaft to make sure it rotates freely before reinstalling pulleys, fans, clutches, belts, and hoses. See Fig. 3
- Fill the radiator and coolant recovery bottle with a correct mixture of fresh, low-silicate coolant and distilled water and check for leaks. Be sure to measure the amount of coolant mixture added to track if there is any air in the system. Purge system of air as required. See Fig. 4
- Note that a small, temporary seepage of coolant from the weep hole may occur during the initial run-in period. This should stop after the seal has been allowed to “lap in.”
- After operating temperature has been reached, shut off engine and allow it to cool – Never remove the radiator cap while engine is hot. Adding cold coolant to a hot system may damage the seal.
- ALWAYS refer to the manufacturer’s repair manual for the exact procedures and specifications when replacing a water pump.
- Finally, always replace the antifreeze when installing a new water pump. Match the type of antifreeze to the manufacturer’s specification. Never substitute or mix types of antifreeze. Also, it is not recommended to use chemical additives.