Modern combustion engines require very specific timing in order to perform their function. For most vehicles these days a timing chain or a timing belt is what is responsible for this. Once upon a time cars even use timing gears to perform this task.
A timing belt, which looks like a standard drive belt that you'll find in the engine, such as a serpentine belt, also has teeth on the inside of it. These teeth make the belt work like a gear. One end of the belt will be looped over the pulley located at the end of your crankshaft. The other end of the timing belt is looped over the pulley at the end of your camshaft. It will also be looped around a tensioner as well to maintain proper tension so that everything happens the way it's supposed to.
When your engine starts to turn over after you put the key in the ignition, your crankshaft is going to turn. That will cause a piston to rise in one of the cylinders of your engine. As the crankshaft turns to do this, the timing belt is also going to force your camshaft to turn in sync with it. As the camshaft turns the valve at the top of your cylinder opens. The piston will rise to meet the open valve and your fuel and air mixture will be injected into the combustion chamber. Your spark plug will then ignite the fuel and air mixture causing a small explosion. That forces the piston back down in the cylinder and keeps your crankshaft rotating. Now speed this whole process up until it happens several thousand times every minute and that is how your engine produces the energy needed to move the wheels of your vehicle and get your car in motion.
The function of the timing belt here is crucial. The crankshaft and the camshaft need to be precisely synchronized otherwise the timing will be thrown off and your engine will not perform the way it's supposed to. If the timing belt were not present at all, your engine simply could not work. Your crankshaft would turn, but your camshaft would be dead and the valves at the top of the cylinders would not open.
If the timing belt breaks while your engine is actually working, you will likely suffer a catastrophic engine failure as a result because those pistons are going to rise up at an incredible rate of speed and crash into the closed valves at the top of the cylinders. All three of those parts will end up getting damaged as a result. It could cause so much damage to your engine that it will cost upwards of $4,000 or $5,000 to either rebuild the engine, or if it's bad enough you may need to simply replace it.
As you can see, the timing belt has an important job to do. And you want to make sure it's able to keep doing that job for as long as possible before you need to replace it with a new one to keep it working properly. Let's take a look at how you know when it's time to replace your timing belt, and the signs that yours is going to die soon.
What Are the Symptoms of a Bad Timing Belt?
Aside from the scheduled time that your owner's manual will detail for when you should change your timing belt there are some signs and symptoms you can be on the lookout for to let you know that your belt is having a problem and you should head to a mechanic as soon as you can.
Distinct Noises: When the timing belt goes bad it will make a sound that nothing else in your engine really makes so you won't confuse it with anything else. The teeth on the belt will begin to wear down and, in some cases, even break off. This will lead to a ticking sound when your engine is working. The very fast paced ticking will pick up pace as you put more pressure on the engine such as when you are accelerating or heading up a hill.
There's also the possibility you'll get a squealing sound when you're having a problem with your timing belt but it's much less frequent than the ticking sound and usually only happens when you're either accelerating or slowing down. This whining or squealing sound is very similar to the sound that a serpentine belt will make when it's failing as well, so you might need to take a look and see if it's one or the other. When you hear the sound from your timing belt it's usually the timing tensioner rather than the belt itself that is causing this to happen.
Engine Misfires: Because your timing belt is responsible for keeping everything precisely timed, if it begins to wear out or stretch out it will not be able to maintain that precision timing any longer. That could lead to engine misfires which occur when the combustion reaction happens too early, too late, or not at all. The combustion reaction won't occur properly in one of the cylinders of your vehicle and your engine will lose power as a result. This will greatly decrease the performance of your vehicle and also cause poor gas mileage as well.
Rough Idling: If you notice that your engine seems to be struggling, maybe your car is shaking, and the engine seems to lurch and sputter. That's the result of rough idling. This can be caused by a problem with your timing belt not working correctly.
Drop in Oil Pressure: Remember when we said that the teeth coming off of the inside track of the timing belt can lead to that ticking sound? Those teeth as they fall off are going to land in the oil pan which is directly below your timing belt. Those little bits of rubber can end up clogging the oil and leading to a drop in overall oil pressure as a result. That in turn can mean your engine will start overheating because there's not the proper amount of oil circulating through your engine to keep it lubricated and cool.
How Long Does It Take to Replace a Timing Belt?
Obviously, the length of any repair job is going to depend on a few different factors. The mechanic you take it to and their skill with getting this job done is the biggest factor. But assuming from the time they actually get the job started until it's done, never mind how long you might have to wait if they have a job to do ahead of yours, you're looking at probably between 1 hour and about four hours to perform this task. There are some rarer models of cars that make it more difficult to get in to see where the timing belt is located to remove it than others, but odds are if you have a more common automobile this shouldn't be an issue for you.
Can a Timing Belt Last 200,000 Miles?
The average lifespan of a timing belt is around 60,000 miles. That's what Toyota would recommend for a Camry, for instance. There are some manufacturers that will recommend your timing belt be changed at a somewhat greater interval. It's not unheard of for a vehicle to make it to 120,000 miles before it needs to have the timing belt changed as is the case with a Volkswagen Jetta. Given the average amount of distance an American driver travels in a year, which is about 13500 miles, your timing belt could last typically between 4 years and 7 years before it needs to be changed. And on the outside edge of things you've got a Jetta which can make it nearly nine years without having the belt changed.
It's not impossible that a car could last for 200,000 miles without changing the timing belt. Of course, that's like saying it's not impossible you can win the lottery as well. It could happen, but you shouldn't be expecting it to happen.
There's anecdotal evidence of cars lasting for 200,000 miles and longer on a timing belt as well. It's been said that you could get 217,000 miles from a Honda Accord, and a Honda Prelude has been rumoured to have gotten up to 230,000 miles. There is even the story of a Plymouth Voyager that managed to make it all the way to 270,000 miles on a single timing belt. And if you dig deep enough into auto forums online you might find tales of the truly rare vehicle that supposedly got to 400,000 miles before the timing belt broke. You should take all of those stories with a grain of salt however because there's no way to confirm it, and if it's only one single automobile that even got that far in the first place does it really matter?
For the safety of yourself, and for the sake of your wallet which is going to suffer for the repair bills you have to pay if you push a timing belt to the point that it breaks, it's best to follow what your owner's manual says and change your timing belt when it needs to be changed before it breaks on you.
What Does it Cost to Replace a Timing Belt?
The actual timing belt itself in your vehicle is not all that expensive. If you were to go to Autozone.com and search for a timing belt you'd see that you can buy a brand new one for between about $40 and $300. These are often sold as kits that include not just the timing belt but a water pump and the tensioner required to do a complete installation. For just a timing belt minus any of the extras like the tensioners and water pump you could get one for as cheap as about $12 to $25.
The real cost of a timing belt replacement comes from the actual labor itself. Because a mechanic really needs to get into your engine to take off the old timing belt before putting the new one on it can take a few hours to get the job done. Depending on the make and model of your vehicle this could take more or less time as well. At the end of the day, you're looking at a substantial labour cost that will bring the entire cost for replacing a timing belt up to anywhere between about $300 and $900 for the average car. A high-end automobile could end up costing significantly more, sometimes up around $1,000 to $2,000. Again, that's not average but it's also not impossible depending on the make and model of your vehicle.
The Bottom Line
Many vehicles these days actually use timing chains rather than timing belts. If you have a newer model vehicle there's a good chance it has a chain instead of a belt, and the lifespan of a timing chain is much greater than a belt. However, if your car is a few years older, maybe it was made before the year 2013, there's also a good chance you have a belt. The only way to know for sure if you don't know right now is to check with your owner's manual because it will tell you. Some older vehicles still have chains, and some new vehicles still have belts; it all depends.
Your owner's manual is going to give you the clearest indication of just how long your timing belt is going to last. As we've seen there is quite a wide range that can go from 60,000 miles to 120,000 miles. With all that distance in between, you never want to take it for granted that your timing belt is still good if you don't know for sure. The best thing is to follow a routine scheduled maintenance and get your belt changed whenever you notice any of the symptoms we've mentioned of a bad timing belt, or when it's run its course and has come down to the end of its projected lifespan.
You never want to have to deal with the potential for a timing belt to break while you're in the middle of driving. You could lose control of your vehicle, and you'll also end up with a hefty repair bill as a result. Make sure you're following that routine scheduled maintenance and know when your belt needs to be changed.