Timing belts control the turning of the cam shaft and crankshaft in a vehicle's engine. When they break, the engine will cease to function. Since cars generally do not show signs of timing belt wear, it is important for drivers to change them regularly. A belt's longevity will depend on the type of car and the owner's manual should provide guidelines for the frequency at which timing belts must be replaced, but a good rule of thumb is to change the belt at least every 60,000 miles.
The belt, which has replaced the chain in modern cars with free-running and interference engines, ensures that the pistons and valves in a combustion engine fire in the correct order at the right times. When the timing belt breaks in a free-running engine, the motor will stop immediately and will not run again until the belt has been replaced. With this type of engine, there tends to be enough space between the pistons and valves that damage will not occur.
Interference engines, on the other hand, are susceptible to damage when a timing belt breaks. The valves and pistons are more likely to collide with one another, which can bend and break them.
There are a few signs that a timing belt is reaching the end of its life for which drivers should watch. If the vehicle is accelerating with less force than usual or if a rattling noise is present when you try to start the engine, the timing belt may soon need to be replaced.
You should not wait until this point to replace a vehicle's timing belt because it wears out over time and a worn belt can cause as many problems as a broken one. wear can create looseness, which may cause the timing belt to slip. When the belt is not operating properly, a vehicle will deliver poor performance if it starts at all, and even if you do get it running, a loose belt can harm the engine.
When it comes time to replace the belt, other major parts will often need to be removed to complete the project, including the water pump. This can be a good time to inspect it and replace it if necessary, since it's already going to be removed from the vehicle.