Mechanics

Water Pump

A water pump is used to circulate coolant throughout the engine block, cooling and heater systems. The water pump is driven by the engine via serpentine belt in most cases. When a water pump fails it can produce a squeaking or rattling sound. Also, a water pump can leak engine coolant through a relief port that allows coolant to pass when the shaft seal fails. This port is created so engine coolant will not contaminate the shaft bearings causing a worse problem. If a failing or failed water pump is allowed to operate it can cause the engine to overheat or completely fall apart causing cooling system or other internal engine damage. The water pump circulates coolant continuously, a thermostat is used to control the rate of coolant flow through the cooling system . A water pump is comprised of a main housing body, flange, main shaft, bearings, impeller, seals and a gasket to seal in against the block.

Water Pump
Water Pump (appearance will vary)

When engine RPM increases so does the water pump flow rate. A water pump will typically last between 60,000 and 100,000 miles. When replacing a water pump always insist on high quality replacement parts to avoid premature failure. To check your water pump condition, make sure the engine is off, next grab a hold of water pump flange and try to move it back and forth. There should be little to no play in the main shaft bearing. If excessive play exists the water pump has failed and needs replacement. Some engine designs have the water pump driven by the engine's timing belt or chain. When this style of water pump design fails it can cause engine coolant to enter the crankcase. This situation can be bad because the engine oil is compromised and can cause the engine to fail from reduced lubrication. The water pump is responsible for supplying coolant to the heater core for proper heater operation. If the water pump impeller is defective it can cause the engine to overheat and cause poor heater performance.

Replacement Guide Outline

Tools needed:

  • Set of sockets and socket wrench with extensions
  • Phillips and standard screw drivers
  • Gasket scrapper
  • Wrench set
  • Gasket sealer (optional)
Replacement Procedure:

  • Start with engine cold, drain coolant
  • Remove serpentine drive belt
  • Remove all accessories to access water pump mounting bolts, remove water pump
  • Using a gasket scrapper remove all of the old gasket and clean surfaces thoroughly
  • Install new water pump with sealing gasket and tighten evenly
  • Reassemble as needed
  • Refill cooling system with coolant and and water mix, then start engine, refill system as the engine warms up
  • Recheck coolant level after the engine has cooled
NOTE: Check for coolant leaks after the job is completed and repair as needed.

Related Replacement Components:

Basic Checks

Low levels of coolant can lead to problems related to engine overheating. Always maintain proper levels of coolant in the overflow coolant reservoir tank. ONLY! Check the radiator when the engine is cold. Only add antifreeze and re install the cap properly. Always drain and refill your cooling system regularly. If further technical assistance is needed, ask our team of certified car repair technicians.

Related Car Repair Information

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-19)