Top Causes of Water Pump Failure and Prevention

Most water pump failures are caused by an external issue, and not the pump itself. When replacing a water pump, it is important to investigate the cause of its failure.  Below are 3 top causes of water pump failure caused by external issues and techniques for prevention. 

#1 Contaminated Coolant

Engine coolant protects a vehicle’s engine from extreme heat and freezing temperatures. Quality coolant and water are critical to water pump operation. Contaminated oil is the leading cause for original and replacement water pump failures. Hard water, mixing coolants and system debris are all contributors to coolant contamination. 
Water quality varies greatly and hard water can result in mineral deposits lingering in a cooling system. These mineral deposits can restrict flow and damage seals. Remember to use distilled water when mixing coolant. 

While the wide range coolant colours is largely attributed to dye, chemistry can vary greatly between different products. Combining multiple coolants is not recommended. Use a 50/50 mixture of the recommended coolant and distilled water when replacing. 

To remove lingering debris, completely flush the engine, heater core and reservoir prior to installing a new water pump. Remember to discard old coolant fluids and debris in accordance with local laws.  

#2 Too Much Sealant

Over applying sealant to water pump gaskets is the second leading cause for water pump failures. Excess sealant can be squeezed into the water pump chamber, restrict flow or damage seals. 
Remember: sealant should only be used with fiber gaskets. Sealant is not necessary for rubber gaskets. 

#3 Defective System Components

Bent or cracked fan blades, a defective fan clutch or idler pulley bearings can put stress on the water pump bearing. These additional vibrations on the engine can reduce the life of a water pump’s bearings. Reference the vehicle manufacturer installation instructions for possible speciality tools required when installing a water pump. 

ACDelco water pumps help your engine keep its cool. For information on ACDelco water pumps and other products, visit us at