Why Timing Belts Need to be Replaced Timing belts have replaced timing chains on many of today's engines. Both belts and chains ensure that the crankshaft, pistons and valves operate together in proper sequence. Belts are lighter, quieter and more efficient than chains. Like other components, timing belts wear out. Proper maintenance requires belt replacement at regular intervals - before they break.
Timing belts are on the front of the engine, protected by a plastic or metal cover.
When a timing belt breaks the engine stops. Replace belts before this occurs. Most manufacturers provide a suggested service life and replacement schedule for this critical component. You should ask a technician if your car has a timing belt instead of a timing chain. If the timing belt breaks on a free-running engine, the engine stops and you will need a tow to the repair shop.