Cambelts, timing belts and timing chains are the one service item you can’t afford to gamble on. They keep the engine’s valves and pistons moving in time with each other — and if they snap the result is bent valves and a repair bill that can exceed the value of the car. A timing belt or chain costs a few hundred pounds to change; a wrecked engine costs thousands.

When should it be changed?

Every manufacturer sets an interval — typically somewhere between 5 and 10 years or 60,000–100,000 miles, whichever comes first, for timing belts.

Timing chains are often stated by the manufacturer as never needing replacement, but usually they will be worth changing as well (especially on the 2 litre BMW N47 diesel engines). Age matters as much as mileage: rubber belts degrade even on low-mileage cars. If you’ve bought a used car with no evidence of a cambelt change in its history, treat it as due now.

What we replace

We fit the complete kit — belt, tensioners and idler pulleys — from quality manufacturers such as Gates, Continental and INA, and where the water pump is driven by the belt we strongly recommend replacing it at the same time, since the labour overlaps almost entirely.

Wet belts

Many recent engines — most famously Ford’s 1.0 EcoBoost and the Peugeot/Citroën 1.2 PureTech — run the belt inside the engine, bathed in oil. These “wet belts” have earned a reputation for degrading early, shedding debris into the oil system and causing serious damage well before owners expect. If you run one of these engines and it hasn’t had its belt done, don’t wait for the interval — get it inspected. We replace wet belts at your home, and careful servicing with the correct oil is essential to their survival.

It’s a big job, often paired with a clutch replacement on higher-mileage cars while access is good. Send your vehicle details to our Chelmsford mobile mechanic service and we’ll quote for the complete kit, fitted at your door.