The best time for a vehicle owner to replace a timing belt or chain is before it fails. For mid-1990s and older engines, the recommended replacement interval for most timing belts is usually 60,000 miles. On newer engines, the original equipment belts are made of better materials and typically have a recommended replacement interval of 100,000 miles or more.

If you have the heads off the engine for any reason, or if you are overhauling the engine, you should also replace the timing belt, chain or cam gears. Don’t take a chance reusing an old timing belt, chain or gear set. A high-mileage timing chain that has stretched and is loose can’t maintain accurate valve timing and should be replaced if play exceeds specifications. The camshaft and crankshaft sprockets should also be replaced along with the chain. These parts are included in a typical three-piece timing set.