In a piston engine, either a timing belt (also called a cambelt) or timing chain or set of timing gears is used to synchronize the rotation of the crankshaft and the camshaft. This synchronisation ensures that the engine’s valves open and close at the correct times in relation to the position of the pistons. The belts will transmit the power for steering belt, coolant fan belt, generator and air-conditioner compressor. If these belts is damaged (broken or slip), serious faults could happen to the engine. Therefore, the periodical check is necessary for your car.