1.A novice should buy, at considerable expense, the manufacturer’s shop manual for the specific model vehicle and engine which is to have the belt changed. These manuals are written for professional mechanics, assume some degree of mechanical expertise, are very detailed in that they state belt tensioner values, bolt torques, fastener locations, etc.
2.The task of the timing belt is to sync the valves and the pistons. An engine belt out of time will contact pistons and valves, just like the timing on a WWI aircraft machine gun, which, without a timing mechanism would shoot off the propeller.
3.If your timing belt is broken, then you will need to determine if your engine valves got bent when the belt broke. If it bent the valves, then more major engine repairs would be needed. This is called an interference motor meaning that the valve will contact the pistons if the belt is broken. If the engine is called a non-interference motor, then this means the valves and pistons should not contact each other if the belt is broken.
4.It’s important to always follow instructions specific to your make and model, especially if you’re unfamiliar with the mechanism. The shop manual, though somewhat costly, should pay for itself with a single repair.
5.Timing belts are a wear item. Most are to be changed every 60,000 to 90,000 miles (97,000 km to 127,000 km) for preventive maintenance. They may break causing expensive damage to interference engines due to the collision of valves and pistons as they go out of sync. Having them replaced at intervals is the best way to save yourself from a very costly repair. Do not wait till the belt breaks causing major engine damage.
6.Some vehicles may require a special tool to reach tensioner mounting bolts hidden by the motor mounts, while others are necessary to release a spring-loaded timing belt tensioner. Most engines have a spring-loaded tensioner that can be operated using common sockets and wrenches, though some will require a male hex wrench/Allen wrench.