What do they do?
Drive the camshafts, which control the opening and closing of the engine's intake and exhaust valves.
Precise valve operation is critical to efficient engine operation.
Why replace them?
Timing belts are quiet, efficient and unseen, so they tend to be forgotten.
Over time, they stretch, crack, become brittle and will eventually break.
Breakage will stop your engine dead and could cause major internal damage.
When to replace?
Timing belts should be replaced according to the manufacturer's required maintenance schedule.
Timing belt replacement involves a considerable amount of engine disassembly.