Changing a timing belt is the most expensive routine maintenance job required on many cars. Here’s how to be sure you don’t pay for it when you don’t need it.
The dreaded timing belt change. Nobody likes to do this expensive maintenance job. Once we bite the bullet and it’s done, you may have a decade or as many as 100K miles to go before you need to worry about it again. The receipt from the completed job becomes valuable to you if you should sell or trade the car. But what if you are buying a used car that seems perfect but is at the service interval where a timing belt replacement is recommended? How can you tell if the timing belt has already been replaced?
One CarTalk Community member mentioned to one of our writers several years ago that they had once paid for a timing belt change, only to then discover that the car had already had that service less than 20K miles earlier. Oops. That got us thinking about how this might have been avoided. And as it turns out, there is an easy way to tell – usually.
How to Tell if Your Timing Belt Has Been Replaced
Every vehicle owner should keep track of the maintenance and repairs they have done on their vehicle and keep that information (with original receipts) safely stored. However, in a country where parents can’t even keep track of kids in the backseat, the reality is those receipts are often lost or discarded before the vehicle even leaves the shop.
Look for the Sticker
Automakers and parts suppliers realize that a timing belt is expensive and special. The job properly done can cost many hundreds of dollars and they feel some responsibility to make sure that owners know when the service was completed and how many miles the vehicle had on the odometer at that time. So service technicians have a sticker they use to provide you with that info. For example, the one in our image above was applied to a Toyota Highlander after it was serviced by a Lexus dealer.
Ideally, that sticker will survive under the hood for the next decade or so until it needs to be replaced again. Mark McMullen of G&M Services in Millis, Mass. told BestRide, “All the kits and belts do come with the sticker, I always fill it out and attach it. I cannot speak for anyone else. They can also fall off if the area is not clean.”
What if the Sticker is Missing?
We wondered if there were some clues that might reveal the belt was done in the absence of a sticker. Mark told us, “Sometimes one of the covers can be removed and the engine can be turned by hand to see the brand of the belt. You can also see if it looks old or recent. That can be done in about a half-hour. Otherwise, it can be tough to know for sure.” This method won’t reveal when or at how many miles the belt was changed, or if the water pump replacement (a job that is usually done along with the belt) was completed.
Why is It Important?
Why does changing the timing belt matter so much? The reason is simple: timing belt failure can destroy the engine in many modern cars. There are four main ways automakers design engines. Those with timing chains instead of belts need not worry. Vehicles like the Toyota Prius and Mazda CX-5 often (but not always) have chains instead of belts. Timing chains are designed to last for the life of the vehicle. These are the minority of engines today.
Then there are two different types of valve and head designs. One design has valves that will be slammed by the pistons if the belt breaks. These are called “interference engines.” The valves interfere with the pistons when the engine turns if the belt is broken. Those that would not have this catastrophic contact are called “non-interference” engines.
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.
When in Doubt, Have It Replaced
Given the risks to your engine, if the timing belt were to break, you really can’t afford to guess whether it has been replaced or if your vehicle has a so-called “non-interference” engine. If there’s any doubt, go ahead and replace it. Yes, it will be expensive. But, it will be a lot less expensive than engine replacement, and you’ll know that it was done this time.
This is why you should always ask to see the full maintenance history of any used vehicle you’re looking to buy. When buying from a dealership you may luck out and they might have done the work themselves and have the records. If there’s no receipt for a changed timing belt, always look closely for the sticker proving it was changed. If that’s missing, adjust your valuation of that vehicle to account for the work you will need to do. Looking for a pre-owned vehicle from a reputable dealer? A great place to get started is right here!