When Should I Change My Timing Belt?

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Close-up of timing belt on an engine
Close-up of timing belt on an engine/Image Credit: Hebert Santos

When to change a timing belt is both a practical and philosophical question. Your vehicle’s timing belt is a critical component that has to be dealt with as a matter of routine maintenance. However, replacing the timing belt is the most expensive routine maintenance appointment you’ll have to make for many vehicles. So, it’s understandable that many drivers prefer to wait as long as possible before having the timing belt replaced. But waiting too long to have this done can have devastating consequences. Here’s how to decide whether it’s time to bite the bullet and have your timing belt replaced.

Why Is It So Important?

The function of a timing belt is to coordinate the combustion cycle of an internal combustion engine. There are a lot of moving parts in your engine; if they bump into each other, you’re going to have big problems. The timing belt connects the crankshaft to the camshaft and ensures that they (and all their associated parts) move in time with each other. Let one break, and the engine might be scrap metal.

Or maybe not. Some engines don’t have what is referred to as “interference”: meaning they don’t have parts that smash into each other if the timing belt goes. In an interference engine, one or more valves in the fully open position extend into an area that the piston may travel into.

The thing is, what qualifies as a non-interference engine is a bit complicated. As engines have become more complicated, it’s not always clear whether your engine will be relatively safe from damage in the event of a timing belt failure. Any engine can be damaged as a result of a broken timing belt and it’s best to assume that yours will be if you let that happen.

Does Every Engine Have a Timing Belt?

So, we’ve established that the timing belt is a critical component and you shouldn’t allow it to fail in your engine. But, not every engine has one. Some engines actually use chains instead of belts. Timing chains are made out of metal instead of the synthetic rubber compounds used in belts. For that reason, timing chains tend to last much longer than timing belts and don’t need to be changed as part of routine maintenance. So how does one know if their car has a timing belt and if so, when to change it?

How Do I Know if My Vehicle Has One?

vehicle owner's manual
The best source of info on your car is the owner’s manual/Image Credit: Artfoliophoto

Automakers seem to have no loyalty to either timing chains or belts. Toyota, for example, goes back and forth even within the same model. Of course, automakers could stamp that on the plastic engine cover, but that would take all the fun out of it. The best place to find out if you have to maintain your timing belt is in your vehicle’s owner’s manual.

Generally, the routine maintenance schedule will have it somewhere between 70,000 and 110,000 miles. Also, take note of the yearly change interval if you drive less than the normal 12,000 miles automakers expect you to travel in a year. Although we have great respect for dealership service centers and their truthfulness, we would suggest using the owner’s manual as your guide rather than a booklet the dealer put on the payment desk. Those tend to be a little too general for our liking.

How Do I Know if It’s Time to Change My Timing Belt?

Now the philosophical part. Let’s say it is the end of winter and you own a car that has 85,000 miles on it and the owner’s manual says to change the belt at 90K. Should you wait until you get to the absolute end of that belt’s life? Not if you are going to keep that car. Your cost of ownership is unchanged whether you do it now or in a year. Either way, you pay. Once the car is past its drivetrain warranty, you are on your own. Why not get it done a bit sooner rather than later? The longer you wait, the more you risk damaging your engine.

Can I Replace My Timing Belt Myself?

Next is the question of who should do the work. If you are a solid mechanic, going it alone will surely save you money. You will also save a few shekels by using a local (trusted) mechanic. However, if ever there was one service you may wish to have done at the dealership, this would be it. The work is important. Getting it done right and getting a one-year warranty on the parts and labor are very important as well.

Finally, don’t be surprised if the mechanic advises you to also change the water pump and possibly some other hardware. The timing belt is part of an interconnected system of pulleys and other components that work together and often wear down together. Replacing a fuel pump now could save you money later when you’ll need to have all the same things taken apart anyway. There may also be service items that fall on the same schedule, like coolant.

The timing belt service is expensive so if you know it’s coming up, you may want to call around, wait for a dealership coupon, and then take the plunge. On most cars, it is a one-time expense and it’s better to do it early than too late. Be sure you keep that service receipt. Anyone you sell the car to will want to see it. And don’t forget, you can find your next vehicle right here in just a few clicks!