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A car or truck’s water pump is an important part of its cooling system. If a vehicle overheats or loses coolant while driving, it may be time to have the water pump inspected.



What Is a Water Pump?

A vehicle’s water pump circulates coolant through its engine and radiator. Water pumps are typically mounted on the front of the engine, which is the side opposite the transmission. You may also be able to locate the water pump by following your vehicle’s upper radiator hose from the radiator to where it connects to the engine.

How Does a Water Pump Work?

he water pump uses rotational energy from the crankshaft to spin an impeller that circulates coolant through your vehicle’s cooling system. Think of it like a boat propeller mounted inside of the engine, designed to move water around to cool all its hot parts. Malfunctioning thermostats and water pumps may cause a vehicle to overheat during normal use.

How is a Water Pump Made?

Water pumps are made of a handful of components, including a housing, a shaft, and an impeller. The water pump housing is the most visible component. After removing the water pump, you may find the star or wheel-shaped impeller is made of steel or plastic.

Some water pumps have a belt-driven pulley mounted on the shaft. Others are driven using internal gears. Water pump components are often manufactured using heavy factory equipment; however, they may be assembled either by a machine or by hand. You may be able to replace just the housing or impeller to repair the water pump, depending on the design of the particular water pump. Rebuilt kits are often available to help restore a failing water pump without having to purchase a new assembly.

Why do Water Pumps Fail?

  • The impeller becomes loose on the shaft and free spins while the engine is running.
  • The housing may become cracked and leak coolant.
  • The impeller may become worn, reducing its ability to circulate coolant through the system.
  • Coolant that contains particulate matter puts extra stress on the water pump’s components.
  • The belt may break or the pulley may become worn. For units that use internal gears, the gears may eventually wear out and need to be replaced.

What Are the Symptoms of Failure?

  • The vehicle overheats after 5-10 minutes of idling time.
  • A coolant leak traced back to the water pump housing.
  • The system fails to pressurize as the engine reaches operating temperature.

What Are the Consequences of Failure?

  • An overheating engine can result in major engine damage if left unaddressed.
  • Spilt coolant is a hazard for pets and wildlife.

Broken water pumps are often mistaken for malfunctioning thermostats, clogged radiators, reduced cooling jacket volume, improperly installed coolant lines, and dozens of other automotive problems. If your vehicle is overheating, and you’re not sure how to diagnose the issue, call your local Pep Boys and schedule an appointment before the problem gets worse.

If you have questions or concerns about water pumps or any of your vehicle’s cooling components, come into your local Pep Boyswhere we can answer any question, help you find any part, or perform any vehicle service you might need.