You might think a water pump doesn’t sound very exciting or important, and a bit of water dripping underneath your car isn’t too big a deal. Well, a broken or damaged water pump can easily lead to severe engine damage, including a chance of it seizing completely.

We don’t have to tell anyone just how expensive repairing engine damage is. In many cases, it’s way more than the car’s worth. So, just what is a water pump (in a car, of course)?

What does a car water pump do?

Your water pump creates a steady flow of coolant around your vehicle’s cooling system. It establishes the proper circulation to keep all the parts working under their optimum temperatures and that all the excess heat is dispensed safely into the environment.

The coolant flows through the engine block, picking up the excess heat, and then through cooling galleries to dispel it. Without the pump the coolant couldn’t flow around these critical components, would evaporate, the engine would overheat, and possibly seize.

The timing belt drives the water pump—often called the Serpentine belt—and their relationship is vital to the survival of your engine. We’ll look deeper into this a little later in the article.

What does a car water pump replacement cost?

The price of water pump replacements can vary considerably from car to car. The job could cost as little as £200 or well over £500. The average price in the UK is around £350, but if you choose Fixter to find you a great deal in your area, you could end up paying quite a lot less.

How can you tell if there’s something wrong with your water pump?

  • The first things to look for are puddles or pools of coolant under your car—especially around the engine.
  • If you lift the bonnet and you see fluid around the engine bay where the water pump sits, that’s a sign there could be a leak or a seized pump.
  • The car won’t start (it could be too late, by this point).
  • Your engine temperature is higher than normal or overheating.
  • The engine temperature warning light has illuminated on the dashboard.
  • There’s steam coming from your engine.
  • You can hear whining, knocking, buzzing or squealing sounds.

How long does a car water pump last?

This is a tricky area to pinpoint, as there are plenty of cars on the roads, still running as well as they ever did on a water pump with over 200k miles of service. That said, there are probably just as many that failed covering distances of only 50k or 60k miles.

Manufacturers suggest that their pumps should be able to provide around 100k of service, so depending on your vehicle usage, you should consider a replacement anywhere between 50k and 100k miles.

Another schedule, suitable to most drivers, is to replace it—along with your timing belt—around every 5 years.

If you still have your owner’s manual, it’s always a good idea to see what the manufacturer recommendations are. Every car operates under slightly different pressures and conditions, varying the lifespan of their components. Only your manufacturer will understand the precise, expected lifespan of each of those that operate inside their vehicles.

The relationship between your water pump and the timing belt

Because the function of the water pump relies heavily on the condition of your timing belt, it’s standard to replace both at the same time.

Another reason for carrying out the work together is that there’s a lot of effort involved accessing the water pump, removing it and replacing it. Carrying out all of that work twice, just to change the belt that drives it—and paying for it—provides a false economy. And now you’re wondering, ‘How long does it take to change a water pump?’ Well, we’re glad you asked.

How long does it take to replace a water pump?

Replacing a water pump can be a steady half-day’s work. A simple and straightforward switch might only take 2 hours, but some of the more complicated could take even the most competent mechanic a full day.

We’d suggest between 2 and 4 hours for the majority. And at anywhere between £60 and £120/hour, that makes for a generous looking bill.

How to replace a water pump

We wouldn’t advise that anybody without the appropriate experience should take on replacing a water pump. It’s a tricky job, and if the new pump isn’t fitted correctly, or the belts that drive it, it could easily lead to ruining your engine.

  • Before you do any work, make sure the engine has cooled down, and all associated components are cool enough to work with. Engine coolant—and the parts they flow through—operates at very high temperatures. The risk of burning or scalding yourself is high. Safety first. Always.
  • Drain the coolant and remove any parts that obstruct access.
  • Remove timing belts or chains, and disconnect hoses.
  • Timing belts, alternator belts, or timing chains often function under tensioners and pulleys. This is a specialist job, and one best left for a trained mechanic.
  • Your mechanic may decide to replace the thermostat and/or radiator cap, or any gaskets and seals that show signs of leaking or age.
  • The pump can now be safely removed and replaced.
  • Apply even beads of sealant along the edges of the parts where the manufacturer recommends a sealant over gaskets.
  • Once all bolts are tightened—evenly to the recommended torque—and the hoses reattached, refill the cooling system with the recommended coolant.
  • Manually test that the pump rotates freely.
  • Following the completed replacement, carry out a leak test to make sure all seals are intact.

Can you drive with a broken water pump?

Given how vital the operation of your water pump is, we’d highly recommend that you NEVER drive your car showing any signs of a faulty or leaking water pump.

It’s far better to have the car towed to a garage or inspected in situ, to determine its condition.

Take care of your water pump, and it should take care of you

Running the risk of your water pump failing by putting off replacement until the last minute is gambling with your engine’s life. It’s true that some motorists achieve twice the recommended lifespan of their water pump and timing belts, but for engine repairs that run into the thousands, is it really worth it?

Ask your mechanic to take a look at your timing belt and water pump to estimate what sort of condition it’s in. Or, if you can remember, or have the paperwork for the last time you had it changed, check if it’s about time you had a new one.

Before you need a new engine.

About Fixter

Fixter is revolutionising the car maintenance industry, one repair at a time. Fixter was founded to make car maintenance as easy as booking a taxi. Digital, transparent and stress-free, with world-class customer service. Since launching in Manchester in 2017, Fixter has expanded to more than 100 cities across the UK and provided thousands of car owners with honest, convenient and affordable car repair services.