What Does A Water Pump Do In Your Car’s Cooling System?

Water Pump: The water pump is either driven by the fan belt or the timing belt on some newer vehicles. The pump moves coolant from the radiator, through the engine, and back into the radiator. The pump has a shaft with a pulley on one end and a pump rotor on the other end. When the pulley is spun by a belt, the rotor moves the coolant.

The term “water pump” is a bit of a misnomer. The pump that cools an engine can carry water, but on modern cars it generally carries a coolant, which is much more efficient than water in cooling the engine. However, many mechanics do refer to this part as a water pump for simplicity’s sake. The purpose of a water pump is to keep the engine cool. Even in cold weather, a combustion engine can generate a great deal of heat and this must be mitigated by the water pump and cooling system.

How a Water Pump Works

The water pump works by pumping coolant through the engine block. The pump forces the coolant through a series of hoses that circle around the engine’s cylinders where it absorbs heat from the engine. The coolant then travels through the cylinder head and out to the radiator, where the heat from the coolant can escape. The coolant finally flows back to the water pump, which sends it back towards the engine so the process can repeat.

Types of Water Pumps

There are two main types of water pumps in modern cars: mechanical and electric. Mechanical water pumps use the physical motion of the engine to drive the coolant out of the pump, while an electric water pump uses the car’s battery to do the same thing.

Mechanical Water Pump

Electric Water Pump


Less strain on alternator

Less investment at installation

Common as manufacturer’s model

More fuel efficient

Able to compensate for weather


Runs at same rate of engine no matter what the outside temperature

Less fuel efficient

Can subtract from car’s horsepower capability

Not as powerful overall

Not as durable over time

Mechanical water pumps are by far the most common type of water pump found in a standard car. However, there can be benefits to switching to the electric option, particularly for those drivers with high performance cars who require maximum horsepower and efficiency. No matter which type of water pump exists in any car, the essential function is the same.

From: autoeducation.com and ebay.com

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