Also called cambelt, timing belts
Draft: this page has not had its final check yet, so check the sources behind anything you rely on.
A toothed belt that turns the camshaft in step with the crankshaft, and wears out, so it is replaced on a schedule.
History: facts, each with the kind of source it rests on
A timing belt, also called a cambelt, is a toothed belt that keeps the camshaft turning in step with the crankshaft, so the valves open and close at the right time for the pistons. Most are rubber, and some are polyurethane or neoprene. A published reference
Every generation on the site whose dossier or engine names it
Reputation: what owners and the press report. Tap one to see what to check.
What to check: Ask when the timing belt was last replaced, and look for a sticker or a receipt.
Belts wear over time, so replacing them at set intervals is recommended, and a rubber belt gives no warning before it snaps. In an interference engine a broken belt can let the valves hit the pistons.
A published reference
Replacing the water pump with the belt is often recommended, since it wears too and is easy to reach then, and a seized pump can break the belt. Belts are often sold in kits with the pump, tensioner and idler pulleys.
A published reference