When to change a timing belt is both a maintenance and philosophical question.
The dreaded timing belt change. Not only the most expensive single maintenance visit but also the one with the most severe penalty for skipping. Timing belts in engines help make sure that the pistons and valves don’t occupy the same space in the engine at the same time. 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 extends into any area that the piston may travel into.
To find out if your engine’s pistons will come in contact with an open valve, AGCO has a handy guide.
Then there are those lucky folks with engines that use chains instead of belts. Timing chains are usually much longer lasting and often are not 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?
Automakers seem to have no loyalty to either timing chains or belts. Toyota goes back and forth even within the same model. To help clear up confusion Toyota has a website dedicated to listing which cars and trucks have which type of engine. 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 car’s owner’s manual. Generally, the routine maintenance schedule shows it someplace after 70,000 miles, and somewhat less than 110,000 miles. Also, take note of the yearly change interval if you drive less than the normal 12,000-mile minimum automakers expect you to. 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.
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? Remember, wait too long and the downside is huge.
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. This is normally part of the job. As is changing the coolant. One final suggestion. Ask the dealership to use “Pre-mixed” coolant. It is the best way to ensure that tap-water does not end up in that engine along with its dissolved magnesium, iron, and calcium. The timing belt service is expensive so call around, wait for a dealership coupon, and then take the plunge. On most cars, it is a one-time change and well worth doing just a tad on the early side. Be sure you keep that service receipt. Anyone you sell the car to will want to see it.
Top of page photo by John Goreham. Second Image courtesy of Dayco and Youtube.