Volkswagen Passat Timing Chains Available Here. The primary purpose of timing chains in a vehicle is to make sure the engine’s valves all open and close at the proper times. A timing chain is essentially the same as a timing belt but generally speaking has a much longer service life. it is important to follow your car’s service plan and replace the timing chain per the manual’s recommendation. Replacing timing chains before they break is cheaper than replacing an engine afterwards. We keep in stock a wide range of timing chains and timing chain kits for all makes and models of car.