Timing Belt
The timing belt is responsible for running the gears that open and close the valves. As the engine is running, air and fuel are sucked in which is then compressed, ignited and exhausted out. The timing belt synchronizes the valves to open and close at the precise moment so everything runs in a smooth, constant timed motion.
What can go wrong?
The timing belt has teeth to control the gears in a constant motion which can be thrown off by a particular movement, causing the engine to stop functioning and damage itself. The valves will begin to open and close at the wrong time while being struck by the pistons, resulting in a costly restoration.
What can you do?
If you notice any unusual sounds coming from your engine such as scraping or slapping; the timing belt may be loose which should be serviced right away before serious damage can occur. Always get the timing belt serviced when required to avoid unnecessary damage.