Timing belts are the "Rodney Dangerfield" of all the belts in your car -- they don't get no respect! Many of today's cars are equipped with a timing belt in place of the old timing chain. The function of this small yet critical part is to keep your engine mechanically "in time."

In a four-stroke internal combustion engine (intake, compression, power, exhaust) the top half of the engine must be synchronized (or in time) with the bottom half to complete the four-stroke cycle. The timing belt achieves this by meshing with cogs connected to the crankshaft and camshaft. The driving of these components in perfect time achieves the four-stroke cycle, producing power in the engine.

The timing belt is made out of rubber and is subject to wear and tear due to mechanical and environmental conditions. The environment of the engine is quite hostile. Temperatures under the hood in excess of 500 degrees, the presence of corrosive fluids such as oil, hydraulic fluids, and battery acid, and mechanical hazards in the form of metal and hard plastics -- all these factors make the path the timing belt must travel perilous -- to say the least. It is extremely important to periodically check the wear of such an important and vulnerable part of your automobile.