What is the function of the timing belt?

In a four-stroke internal combustion engine, the top half of the engine must be synchronized with the bottom half in order to complete the four-stroke cycle of intake, compression, power and exhaust. The timing belt keeps the engine mechanically "in time".

How does it work?

The timing belt keeps the engine synchronized by meshing with cogs connected to the crankshaft and camshaft. By driving these components in perfect time, the four-stroke cycle is achieved, resulting in power in the engine. 

Why should the timing belt be a part of your regular service check-up?

The timing belt is made out of rubber and the hostile mechanical and environmental condition of the engine makes it particularly susceptible to wear and tear. Temperatures under the hood can exceed 500 degrees. The engine is also filled with corrosive fluids such as oil, hydraulic fluids, and battery acid. Then there is the added problem of mechanical parts, which are made of hard plastics and metal. These factors added together can wreak havoc on the timing belt. That is why it is extremely important to periodically check the wear of such an important and vulnerable part of the car.