What is a Timing Belt?
The rubber belt that keeps your engine's valves and pistons in perfect time.
Simplified animation — not to scale.
In plain English
A timing belt is a toothed rubber belt that connects the crankshaft (bottom of the engine) to the camshaft (top). It makes sure the valves open and close at exactly the right moment as the pistons move up and down.
"Like the chain on a bicycle linking the pedals to the back wheel — if it snaps mid-ride, everything stops in a bad way."
How it works
As the crankshaft turns, the belt drags the camshaft round in perfect sync. If the belt snaps on most modern engines (called "interference" engines), the pistons can crash into open valves and destroy the engine. That's why manufacturers specify a strict replacement interval — usually every 60,000–100,000 miles or 5–6 years, whichever comes first.
Signs of trouble
- ⚠You're approaching the manufacturer's mileage/age interval
- ⚠Ticking or slapping noise from the front of the engine
- ⚠Oil leak from the timing cover
- ⚠Engine misfires or won't start
- ⚠Visible cracks or missing teeth on the belt
£400–£900 fitted — far cheaper than a new engine
Always get a written quote. Prices vary by car, region, and parts brand.