To understand why properly looking after the timing belt is so important, it’s vital to understand how an engine works. An engine has pistons that race up and down inside cylinders. They are activated by a series of explosions in those cylinders. To supply the cylinders with fuel and air when required, valves must open at precisely the right time. To make this happen, the timing belt unites the camshaft that controls the valves with the crankshaft that is turned by the pistons. In short, the timing belt keeps the engine perfectly in sync with some of the most important components and ensures the engine doesn't grind to a complete halt.

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WHY DOES THE TIMING BELT NEED REPLACING?

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The timing belt (or cambelt as it's sometimes referred to) is a toothed belt made out of a mix of rubber and various other materials such as Kevlar. They’re subject to a lot of heat in the engine bay and may also have to put up with wear caused by dirt and debris. Over time, the belt can lose teeth and perhaps slip or even snap. Any of these scenarios are often fatal for an engine!

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when should the timing belt be replaced?

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The manufacturer will recommend when to have a timing belt replaced. These err on the side of caution. Stick to the recommended servicing schedule and you can be confident your engine is unlikely to suffer a cambelt failure. Exceed the limits and you may be OK, but it really isn't worth taking the risk given the potential outcome should anything happen.

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SIGNS YOUR TIMING BELT MAY NEED REPLACING

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Your cam belt might need replacing sooner than your vehicle manufacturer’s schedule recommends. There are a few tell-tale signs to look out for and things that can go wrong:

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Noises from the engine

You should check out any unusual noises from the engine straight away. Cam belts don’t usually give much notice before they fail, but a rubbing sound from the belt cover area is a sign it’s about to fail. If you hear it, switch the engine off!

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Car won’t start

If your car won’t start, it could mean there’s a problem with the cam belt. If the cam belt’s broken, then the cam shaft won’t rotate when the crankshaft turns, so the car may not start at all.

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TIMING BELTS VS TIMING CHAINS?

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Depending on the kind of car you have, it will probably have either a timing belt or a chain. As the names suggest, the belt is made from rubber, the chain from metal. As a general rule. timing belts need to be changed every five (5) years or usually between 30,000 and 60,000 miles (whichever comes first). Chains last longer, needing to be changed at around 100,000 miles. Sometimes they’ll even last the lifetime of the engine!

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HOW TO FIND OUT WHAT YOU HAVE

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Your first port of call should always be to check your car’s user manual. Timing belt, camshaft belt or cambelt should be mentioned in the index and it will certainly be on the service schedule. Doing this simple piece of research will also help you to find out if your car has a belt or chain. On modern cars, it’s usually the case that models with smaller engines have timing belts; those with larger engines have chains.