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Cooling

What is a Water Pump?

Circulates coolant around the engine.

WATER PUMP — CENTRIFUGAL IMPELLER CUTAWAYDrive beltEngine blockCoolant in (from radiator)Pressurised coolant outWeep hole — drips mean the seal is failingImpeller vanes fling coolant outwardAlloy housingBelt-driven — many pumps run off the timing belt, so change them together

Simplified animation — not to scale.

In plain English

A belt- or chain-driven pump (sometimes electric) bolted to the engine that keeps coolant flowing through the cooling system whenever the engine is running.

A simple analogy

"It is the cooling system's heart — when it stops beating, the engine quickly gets a fever."

How it works

As the engine spins, it drives the pump's impeller, which pushes coolant out of the engine and through the radiator in a continuous loop.

Signs of trouble

  • ⚠Coolant leak from the front of the engine
  • ⚠Whining or grinding noise
  • ⚠Engine overheating
  • ⚠Steam from under the bonnet
Rough UK cost

£250–£800

Parts: £40–£200
Labour: £200–£600 (often combined with timing belt)

Always get a written quote. Prices vary by car, region, and parts brand.

Heads up: Carautonomy is for general guidance only. If your car is showing warning lights or behaving oddly, get it looked at by a qualified mechanic.

Keep exploring

Alternator
The on-board power station that keeps your battery topped up.
EGR Valve
A small valve that recycles exhaust gas to reduce emissions.
Starter Motor
The muscle that turns your engine over when you twist the key.

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A friendly note

Information here is general guidance, not a diagnosis. Always speak to a qualified mechanic before parting with cash.

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