Timing chains, belts and engine repairs

What does this page cover?

Timing chains, cambelts and the engine repairs that often go with them, on BMW, MINI, Mercedes-Benz, Audi, Volkswagen, SEAT, Škoda, Land Rover and Range Rover engines. The pages further down go into detail engine by engine.

Does my engine have a timing chain or a cambelt?

It depends on the engine, not the model name. The EA111 1.4 TSI petrol, built from 2005 to 2015, uses a timing chain. The EA288 TDI diesels use a dry camshaft belt, plus a second belt that runs in the engine oil and drives the oil pump.

Send us the registration and we will check which your engine has.

What are the signs of a worn timing chain?

The usual sign is a rattle or metallic noise, often when the engine starts from cold, and on some engines only for a few seconds. As the wear goes on, some engines show reduced power, misfires or warning lights.

A belt that runs in oil usually gives no warning before it fails. That is why the car’s own schedule matters more than waiting for a symptom.

How do you confirm it before fitting parts?

A fault code is not a repair, and a rattle is not a diagnosis. Depending on the engine, we:

• listen to the engine at a cold start
• read the fault data stored in the engine control unit, including camshaft timing faults
• measure how far the chain has stretched, or check the camshaft timing
• inspect the chain, guides and tensioners
• on some engines, check the oil for metal particles and for fuel

We then show you what we found and send a written price. No part is fitted until you give your written approval.

What does the repair involve?

It depends on what the checks find. On many engines we replace the chain, guides, tensioners and sprockets as a set, not just the chain. On others, the measurement shows the tensioner alone needs replacing, or the repair is done in stages and each stage is priced in writing.

Where something else caused the wear, such as fuel-diluted oil, we put that right too, so the new parts are not exposed to it. Once the work is done, we check that the noise has gone and verify the repair, including a road test where appropriate.

Cambelts are replaced with the tensioner and water pump, at the interval in the maker’s maintenance schedule for your engine.

Which page covers my engine?

BMW and MINI

• BMW timing chain: a rattle from the back of the N47 diesel, and chain wear checks on the N20 petrol.
• MINI timing chain: a loud cold-start rattle from the N14 in the R56 Cooper S and John Cooper Works.
• VANOS and cam timing: limp mode with camshaft timing faults.
• Oil leaks: oil filter housing and rocker cover gasket leaks.
• Turbo: lack of power, noise or smoke, with the oil supply checked before the turbo is condemned.

Mercedes-Benz

• Mercedes timing chain: a rattle for a few seconds after start-up on the OM651 diesel and the M270 and M274 petrol engines.
• Oil cooler leak: oil collecting in the V of the OM642 V6 diesel.

Audi, Volkswagen, SEAT and Škoda

• VW Group timing chain: a metallic noise after start-up from a stretched chain, for example on the 1.4 TSI.
• Cambelt and water pump: cambelt, tensioner and water pump replacement at the interval in the maker’s schedule.
• Wet belt engines: which TDI diesels have an oil pump belt running in oil.

Land Rover and Range Rover

• Ingenium timing chain: a cold-start rattle from the 2.0 Ingenium diesel in the Discovery Sport, Evoque, Velar and Discovery 5.
• 5.0 V8 timing chain: a rattle at idle or on a cold start from worn chain guides.
• TDV6 and SDV6 turbo: low power, a whistle or limp mode, with the actuator and oil supply checked first.

Should I check for a recall first?

Yes. Whether a recall applies depends on the individual car, so check your registration on gov.uk. Recall work is done by the manufacturer’s network, not by us.