Your car’s timing belt (cambelt) controls the order and frequency in which the engine’s valves open and close. Timing belts are subject to wear & tear and should be replaced at regular intervals to prevent snapping, something that would be disastrous for any engine. If your engine is rough idling or misfiring, you may require a new timing belt.

Timing chains are an alternative to timing belts (cambelts), they are commonly found in newer vehicles (eg, all BMW models since 1993). Timing chains are a more reliable solution which last longer, at the expense of being more labour intensive to repair, and more destructive when they fail. If your engine is misfiring, or you notice a rattling sound when idling, you may need a replacement timing chain.