Timing belt or timing chain? When to replace it and the warning signs

Belt or chain: what is the difference

• Timing belt: a toothed rubber belt behind a plastic cover. It wears with miles and age and must be replaced on schedule.
• Timing chain: a metal chain inside the engine, lubricated by the engine oil. It is meant to last much longer, often the life of the engine, but its guides and tensioner can wear.
• Not sure which one your car has? It is listed in the maintenance schedule in your owner’s manual, or we can tell you from the year, make, model and engine.

When a timing belt is due

The interval is set by the manufacturer, commonly somewhere between 60,000 and 100,000 miles, and many also give a limit in years because rubber ages even when the car sits. If you bought the car used and there is no record of a belt change, treat it as unknown and get it checked.

Why you should not wait for it to break

Many engines are "interference" engines: the valves and pistons use the same space at different moments, and the belt keeps them apart. If the belt snaps, the engine stops immediately and the pistons can hit the valves. That usually turns a planned maintenance job into a major engine repair. Even on engines where that does not happen, a snapped belt leaves you stranded wherever it breaks.

Warning signs

• A ticking or slapping noise from the front of the engine.
• Oil leaking near the timing cover. Oil on a timing belt makes it wear faster.
• On a chain engine: a rattle for a few seconds at cold start that gets longer over time.
• A check engine light with codes for the camshaft and crankshaft being out of step, or the engine running rough.
• The engine cranks but will not start at all, which can mean the belt has already broken. Don’t keep cranking it.

What usually gets replaced with it

The tensioner and idler pulleys wear along with the belt, and on many engines the water pump is driven by the timing belt behind the same covers. Replacing them at the same time often makes sense, because most of the labor is getting to them. We explain what is worth doing on your engine and why.

How we handle it here

• We confirm whether your engine has a belt or a chain, check its service history and tell you when it is actually due.
• We replace timing belts and repair timing chain problems in our shop.
• We give you the price before any work starts, nothing is done without your approval, and you can ask for a written estimate.
• We are open 24 hours a day, 7 days a week, and we speak English and Spanish.