TRUCKEE, Calif. - We all try and do the best we can to protect our vehicles and make sure to keep them maintained against all possible threats and dangers. However, it should not be surprising to learn that one of the greatest dangers to high mileage cars is also one of the least well-known. While we try to prevent cases of engine or transmission failure, the death of many older or high mileage cars is nothing other than a failure of the timing belt.
In order to understand what makes the timing belt so important and how we can prevent it from failing, we first need to learn a little bit about what it does and what we should expect from specific car models when it comes to life expectancy of the belt.
Timing belt replacement is the "must-do" service operation which every car owner should know about. And, we should be aware of whether our engine is considered an interference engine or not. These two bits of information can, at a minimum, save us from unexpected breakdown and in the extreme can help us avoid thousands of dollars in repairs.
Without getting too technical, the synchronization between two internal engine parts (the crank and cam shafts) is accomplished with the help of the timing belt. In the process of these two parts moving, the valves open and close in close proximity to the pistons. This constitutes an interference engine, because if the timing belt jumps a tooth on the sprocket on which it rides or the belt fails altogether, the valves and pistons will "interfere" with each other.
This collision will cause major damage to the engine. The repair bill will, on older vehicles, often exceed the value of the car. On the other hand, a car whose engine is not configured this way will simply lose power or will not start. While this might be more desirable than facing huge repair costs, it is something that is better avoided if possible.
If all of this sounds like a nightmare, that's because it can really turn out to be one. Luckily though, timing belt failure is somewhat easy to prevent, and although it may not be the cheapest or easiest operation in the world, it is definitely a better option that purchasing either a new car or a new engine.
Of course, checking to see when your timing belt was last changed is not always the easiest task either. If you have owned your car, and have ever had it replaced in the past, you should have the mileage written down as to when it was changed.
If, though, you purchased your car used, there may be a sticker located under the hood of your car that gives the mileage of the last change. If you cannot find this sticker, than it may be better to have the belt changed, just to be on the safe side.
If you have the owner's manual for your vehicle, it should detail when the belt should be changed. If you have trouble finding out when exactly the belt should be changed; you could consult either a local mechanic or contact a dealership for the exact number.
A good general rule of thumb is that a timing belt should be changed every 60,000 to 75,000 miles, although some belts are designed to last up to 100,000 miles before requiring a change.
Regardless, it is best not to let a belt go more than 80,000 miles or so, even if the recommended change point is a lot higher. Changing your belt early is definitely a lot safer for your engine, and a little money out of pocket can save you a lot of money and a new car in the long run.
Some other considerations relative to timing belt replacement are:
1) Is the vehicle leaking any type of fluid that might degrade the belt? If so, disregard the suggested replacement interval and replace the belt ASAP as well as repair the leak.
2) Do you know the repair history of the vehicle? If it is not verifiable, err on the side of safety and replace the belt.
3) Timing belt replacement can be labor-intensive. Since the water pump is usually accessed in the same operation you might consider replacing the pump at the same time even if it doesn't leak. You will save on labor and possibly prevent a pump replacement later on that will also necessitate the belt to be replaced again.
4) To avoid subsequent failure, consider replacing sprockets and tensioners that are part of the timing belt system. All components are sometimes sold as a kit and can be less expensive than purchasing them individually.
Remember, even though you may get your oil changed every 3,000 miles, and do all of your scheduled repair services, nothing can save you from a timing belt failure. Make sure to get your timing belt replaced regularly and by a certified mechanic. It can mean the difference between a good running car and useless piece of metal.