
Timing belts have replaced timing chains, in most of the vehicles on the road today.
Consequently, your engine timing belt, is totally different, from “V-belts” or “Serpentine belts”; which are located, on the outside of the engine.
Because, engine timing belts performs, a much more important job.
So, the belt, provides a connection, between the camshaft and crankshaft. As a result, allowing the pistons and valves, to operate in proper sequence.
Timing belts have proven to be, quieter and more efficient, than timing chains. But, those benefits come at a cost. Consequently, they require more frequent replacement, than timing chains. Furthermore, the engine timing belt is responsible for, synchronizing the engine’s many functions. Including, running the water pump.

As a result, it controls the rotation of the camshaft and crankshaft and; the opening and closing, of the engine’s many valves. So, when all this is done, it allows the fuel, to ignite in the combustion chamber at the right time. In order for this process to take place, the valves; have to open and close at the right time.
Consequences Of Wrong Timing

If the timing is wrong, the valves can open, when the pistons are at the top of the cylinder. As a result, your engine can suffer anything from, bent valves to a broken piston. Consequently, you will have to disassemble the top part of the engine; before you know the full extent of the damage. That’s why, the valves have to be, in the correct position as well as the pistons.
There Are Two Types Of Engines, That Use A Timing Belt:
Free-running Engine
If the belt breaks on a “free-running” design, the engine will just stop. There is enough clearance, between the pistons and valves, so no mechanical damage usually occurs. So, it is possible, just replacing the belt, may fix your problem.
Interference Engine

But, if the timing belt breaks, on an “interference engine”, mechanical engine damage will occur. Most commonly, the damage involves, the pistons hitting open valves. Resulting, in the need for expensive repairs. In extreme cases, replacing the engine may be required.
Breakage is not the only reason to replace your timing belt. Looseness and wear, can allow the timing belt to slip. Also, resulting in poor performance, no-start conditions or engine damage.
So, proper maintenance requires timing belt replacement, at regular intervals, before it breaks or wears out. Therefore, the manufacturers provide, a replacement schedule and repair information for this critical component.
How do you know if your vehicle, has a timing belt? How do you know, when it should be replaced? Check out our (PDF) files or your owner’s manual to be sure.
Conclusion
So, the belt itself is inexpensive, probably costing less than $20 at an auto parts store. But, your mechanic will probably charge, several hundred dollars (or more) for a belt replacement. Finally, with something as important as the belt, prevention is better than failure.
Thank You !