I got this question from a long time customer last week. It's a very good question, one that we get a lot. It is a good idea to replace your timing belt at the manufacture recommended interval. There are two types of engines that use timing belt, interference and non-interference. Most Honda and some Toyota engines are interference engines, meaning the valves and pistons occupy the same space at different times. The timing belt interacts with the cam shaft(s) and crank shaft, and times the engine in a way so the pistons and valves do not make contact. In non-inference engines there is enough space so that the valves and pistons do not occupy the same space.
So what happens if my timing belt breaks? Well, in an interference engine, damage is likely to occur. The pistons will stay in motion while the vehicle is still moving, but the valves that are open will stay open. If the valves and pistons make contact damage will occur, can bend valves, break guides, or even damage the pistons.
While we can check your drive belt(s), the timing belt is usually hidden from view under the timing cover. The other belts can be a good indication of what your timing belt looks like, and we check them every time we service your vehicle. Not all engines have timing belts, in fact Honda and Toyota have been making more and more engines using timing chains. Timing chains do not have to be replaced as regularly as timing belts, or at all in most cases.
If if you are curious if your vehicle is due for a timing belt service, or just want to know if your vehicle has a timing belt, let us know.