Timing Belt Replacement: When and Why It Matters

What the Timing Belt Actually Does

The timing belt keeps your engine's crankshaft and camshaft rotating in exact synchronisation, controlling precisely when each valve opens and closes relative to the pistons moving below. This timing has to be exact — even a fraction of a rotation out of sync can cause serious problems.

When It's Due

Most manufacturers specify replacement somewhere between 60,000 and 100,000km, or 7 to 10 years — whichever comes first — regardless of how the belt looks on visual inspection. The exact figure varies significantly by make and model, so check your specific logbook rather than assuming.

Why Failure Is So Serious

On an "interference" engine — a very common design — the pistons and valves occupy the same physical space at different points in their rotation, kept apart only by the belt's precise timing. If the belt snaps, valves can collide with pistons, bending valves and sometimes damaging the pistons or cylinder head. What would have been a scheduled, moderate-cost replacement becomes an engine rebuild or full replacement.

Why There's No Warning

Unlike brake pads, which have a built-in wear indicator, timing belts generally don't announce their impending failure. They can look and sound completely normal right up until the moment they fail — which is exactly why this is a scheduled interval to follow by distance and time, not a "wait until it shows signs of wear" item.

Not sure whether your car has a timing belt or a timing chain (chains generally don't need scheduled replacement), or when yours was last done? See our FAQ: How Often Should I Replace My Timing Belt?