How to Inspect Your Timing Belt

Visually Inpecting Your Timing Belt

Timing Belt
Windell Oskay

Your timing belt is the most important maintenance item in your engine. Think of your timing belt as the conductor of the complex mechanical orchestra that is your car's engine. If things don't happen just at the right time, the whole piece is thrown off.

Does your car or truck have a timing belt? Some do not. Some vehicles have a timing chain only. A timing chain is a different type of system doing the same thing a timing belt does.

Timing chains do not need to be replaced as often as timing belts, but they do tend to be more expensive to replace if they every need servicing. Your vehicle's repair manual will be able to tell you what type of engine you have, as in timing belt or timing chain.

You should replace your timing belt at the manufacturer's suggested intervals regardless of its visual condition, but it's a good idea to do an inspection every 10,000 miles or so. On many cars the timing belt is easily seen by removing the plastic timing cover on the front of the engine, usually held on by a couple of Phillips head screws or clips. On some vehicles, it's more involved to access it, but it's always on the outside of the engine and accessible in some way. Consult your repair manual if you aren't sure how to access and inspect the timing belt. 

To inspect the belt, first look at the outside of the belt to see if any tiny cracks are forming.

The timing belt is a very strong metal-reinforced belt with rubber on the outside. The rubber should be fairly smooth, with no chunks missing or massive cracking. One or two small cracks in the outer shiny coating of the belt are ok, but if you see lots of cracking on the surface this may indicate extreme wear.

Next flip the belt over slightly to inspect the teeth. You can do this at the point that's farthest away from both pulleys. You may not be able to actually "flip" the belt, but you can sneak some looks at the underside of the belt all the way around. A single broken tooth can be catastrophic, so don't decide that you can just live with it as is for a while. Even if your timing belt didn't break, that missing tooth on the back could cause it to do something called "jump the timing." If this happens, all of a sudden your spark plugs and your valves aren't dancing to the same beat, and your engine will run terribly, if at all. Also, check the belt's play by twisting it. If you can turn it much more than halfway around, it might have too much free play. Check your manual to see what your car's specs indicate. This is adjustable, but can often be a fairly involved job. Better safe than sorry!

Don't hold off on timing belt replacement. If it breaks or shreds, you can be looking at some serious repair bills.