What does your timing belt do?

Your timing belt, also known as a cam belt, is an essential part of your car. Here’s why you need to keep it in good working order.

The timing belt in your car is made out of tough rubber with grooves or teeth running along the inside edge.

The belt controls the opening and closing of the engine’s valves by turning the camshaft and crankshaft at the right speeds.

Timing is everything: once your belt shows signs of wear and tear, it will prevent all the parts of your car’s engine from working in sync.

This could end up seriously damaging your engine. Early indications can be poor running and engine warning lights.

It’s important to remember that timing belts are NOT checked as part of your regular MOT.

The belt will have a ‘life’ (4 years is not uncommon) or a mileage, again it will vary considerably by manufacturer, refer to the owner’s manual for guidance.

If the belt snaps, the car can suffer catastrophic internal damage caused by the valves and pistons banging into each other.

The car will be immediately immobile, so on top of costly engine damage, you’ll also have to cover a towing fee to the nearest garage.

How regularly should I change my timing belt?

We recommend you replace your timing belt every four years, or at around the 60,000 mile mark. However, you might have noticed some symptoms of a worn timing belt.

Here are the main red flags that indicate it’s time to change it up:

  • Your engine won’t turn over. If your timing belt has broken, then your engine won’t be able to turn over, although you might hear the sound of the starter motor engaging when you turn the key.
  • Your engine misfires. If your belt is worn, it can slip and cause the engine cylinders to open or close out of sync. You’ll hear a banging noise from the engine and possibly feel a jerking motion. Not cool.
  • As part of a routine service a visual check can usually be undertaken for any oil leaks or belt contamination – this can contribute to early belt failure.
  • Oil leaking. Your engine will tend to leak a little oil from the timing belt cover, this is normal but over time the excess oil can prematurely wear out the timing belt.

When do I need to change my timing belt?

If you’ve got a decent maintenance schedule in place, you can avoid the additional wear and tear that will result in these warning signs. Whether you’ve got a brand new car or a second hand model, you’ll need to work out the recommended interval for changing your belt and make a note in your calendar or car manual. Regular checks will save you money in the long run.

The frequency of your replacements depends on the age of your current belt, the distance traveled and the model of your car. Prices may also vary depending on your location.

How much does it cost to replace a timing belt?

The cost of a timing belt replacement depends on the car make and model – the main cost will be labour, because several parts of the engine need to be removed to get access to the belt. Don’t forget, if you’re keeping to your maintenance schedule you’ll only have to cover this cost every four years or so, which makes it easier on your budget. Replacing your timing belt requires a few new pieces of kit: the belt itself, tensioners and pulleys, drive belts, seals, and usually a water pump/coolant. These parts work together closely, and generally wear to one part will equally affect the other.

Vehicle Fixter Saving
Ford Fiesta
1.6 TDCI
£429.10 20%
Ford Focus
2.0 TDCI
£304.98 19%
Ford C Max
1.8 TDCI
£405.60 17%
Vauxhall Corsa
1.4 Petrol
£393.90 14%
Volkswagen Golf
2.0 TDI
£425.10 18%
Nissan Qashqai
1.5 DCI
£401.70 19%
Toyota Auris
1.3 litres
£274.09 15%
Citroen Berlingo
1.6 litres Multispace
£328.90 14%

The exact cost of timing belt replacement depends on your car brand and model. As before, prices may also vary depending on your location.

Your car’s water pump is typically driven by the timing belt and needs to be removed when a new belt is fitted. That’s why water pumps are usually refitted at the same time as timing belts. They’re inexpensive and tricky to access, so it makes sense to replace them together while your car is already in the garage.

Some engine seals will have been removed in order to access the timing belt, and they tend to lose their strength if they’re reused. It’s always advisable to replace engine seals at the same time as the timing belt: they cost considerably less than the labour involved, so it’s a smart time to make a saving.

What’s the difference between a timing belt, a cam belt and a timing chain?

Good question. There’s a more in-depth explanation in this article about the difference between a timing belt, a driving belt, and a timing chain, but in a nutshell timing/cam belts are made out of toughened rubber and a timing chain is, well, a metal chain.

Timing belts have squared off teeth-like grooves to ensure positive drive is maintained at very tight tolerances, whereas drive belts usually have slightly sloping sides which wedge them into place and drive alternators and air conditioning pumps. They both do the same job, just in a slightly different way.

A timing chain has no maintenance schedule and it’s out of sight inside the engine.

It’s controlled by tensioners which use the oil pressure in the engine. If your oil pressure falls too low, the tensioners will fail and the chain will become slack initially causing a rattle (usually when cold) but will eventually fail – causing considerable damage to the engine.

Timing chains don’t drive the water pump or any ancillaries such as the alternator or air conditioning.

Chains are however reliant upon regular oil changes to avoid blocked oilways which reduce oil pressure – changing a timing chain is usually considerably more expensive due to the amount of internal engine dismantling required.

Got a question about timing belts or any other part of your car? We’re here for you.

Contact Fixter via email at support@fixter.co.uk, or call us for free on 0800 368 8632 (Mon to Fri 7am-7pm).

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