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When should you change your cambelt?


If your cambelt bites the dust, you could face a hefty repair cost. Here's when and how you get it changed.

Fixing cambelt

Not all of us are mechanics in our spare time.

So the prospect of a crucial part of our motor breaking is likely to fill most of us with equal parts dread and confusion.

But while your cambelt is a vital bit of kit, it can be easily sorted by a professional. Here’s how you find out when yours needs changing.

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What is a cambelt?

The cambelt, also known as the timing belt, is one of the most crucial bits of kit in the engine.

It’s basically a rubber belt with teeth on it which synchronises the rotation of the crankshaft and the camshaft.

What does it do?

In a nutshell, it regulates the way your engine works.

It controls the opening and closing of the valves to the cylinders in time to ensure correct combustion in the engine. Its primary role is to control the timing and sequence of the opening and closing.

Like most bits of kit, it will eventually wear out. If it cracks, tears or snaps, it can cause a whole heap of expensive engine damage. With older cars this usually means they won’t be worth repairing.

How often should you change it?

There’s no ‘one size fits all’ rule when it comes to how frequently a cambelt should be changed, as a lot depends on the car.

Most manufacturers suggest either a time- or mileage-based change, depending on which comes first.

There’s a lot of variation between both manufacturers and engines when it comes to when a change is due. This could range from 40,000 miles up to 100,000 miles, and from four years up to six years.

The vehicle handbook will specify the change frequency, and a decent garage should let you know if a cambelt change is due when your car’s serviced.

Manufacturer’s intervals should be treated as the absolute maximum, as failure of the cambelt can cause serious mechanical damage.

Engine cambelt

How much does a cambelt change cost?

The bill for changing a cambelt can vary from around £200 to over £1,000 depending on the make of car and who does the work.

It’s also one of those jobs where, while the part itself may not be hugely expensive, it’s often the labour that can bump up the bill.

Replacing it can take several hours’ work, which involves taking apart the engine block and putting it back together.

Any early-warning signs?

Often there’s no sign the cambelt’s reached the end of the road as it’s so deeply embedded in the engine.

Trevor Eastman, head of technical services at Haynes' automotive team, says: “If a driver is lucky, they may hear a rattling or slapping noise prior to failure. But in some cases even an expert may not be able to predict a cambelt failure”.

And unlike new brakes or other replacement parts, you may not notice any difference in the way your car drives.

 First published 29 September 2016


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