Every driver gets used to the sound that their car makes eventually, and in doing so you develop something of a baseline for understanding how your vehicle is working. When your car starts producing sounds that you're not used to you know right away that something has gone wrong. Even if you're not 100% sure what the sound means, if it's a new noise coming from under the hood of your vehicle then you know you likely have to go get it checked out.
When your timing belt begins to go bad, it can produce some distinct sounds to alert you to the problem that will save you some time in troubleshooting because they're not likely to come from any other part of your engine. So while it's never a good thing to have any part of your car break down, at least you can rely on the distinct sounds a failing timing belt is going to make to help you get to the root of the problem so you can get it fixed as quickly as possible and get your car working the way you need it to again.
What is a Timing Belt?
Any car with a gasoline-powered combustion engine relies on either a timing belt or a timing chain to keep it working properly. The timing belt connects the camshaft to the crankshaft in your engine so that they rotate in synchronization. This allows for the precise timing of the combustion reaction which allows your entire engine to function. If the timing belt is not working properly then that synchronization can't exist. That means your engine could suffer any number of problems from the valves not being open at the correct time in the cylinder to the spark happening at an incorrect time to the fuel and air mixture being injected into the cylinder at the wrong time.
If your timing belt were to fail completely and break, your camshaft would stop rotating while your crankshaft would continue which could potentially end up destroying your entire engine. Even in the best-case scenario if your timing belt breaks, you're going to suffer a catastrophic engine failure and will likely end up with a repair bill for things like damaged valves and cylinders that will cost as much as $3,000 or $4,000. As you can see, taking care of your timing belt is therefore a very important task. When you start hearing sounds that indicate it's having a problem, you need to get it looked at right away.
What Sound Does a Timing Belt Make?
When your timing belt goes bad there are a number of signs that you can be on the lookout for but in particular there are some distinct sounds that a timing belt will make. In fact, you have the potential to hear more than one sound coming from your timing belt if you know what to keep your ears open for.
Because the timing belt has teeth on the inside of it, it is prone to producing a noise that makes it very distinct from other belts that are in your engine such as the serpentine belt when it goes bad. In particular, a faulty timing belt will make a noticeable ticking or clicking sound that is very distinct from any other noise you can expect to hear from your engine. This is the most definitive sign that you have a problem with your timing belt, in fact. While a number of sounds in your engine can sometimes be hard to discern or easily confused with something else, if you hear this noise it is almost certainly an issue with your timing belt which makes it a good indicator that you have a problem that you'll need to address right away.
The clicking sound is produced as your timing belt begins to fail because the belt, as we said, runs between the camshaft gear and the crankshaft gear with those teeth meshing in the gears to keep it in place. When the teeth wear down and sometimes even fall off, it will start producing this very fast-paced, repetitive click as it rotates.
Because of the speed that your timing belt is moving at the noise is extremely fast and is kind of like the sound of a fast spinning roulette wheel if you ever heard one of those. Alternately, it's like one of those large gaming wheels that you might see used for a raffle or something like that. However you liken it in your head, the sound is noticeable and distinct. You don't have a lot of time left to get your timing belt looked at if you're noticing this sound and it could potentially break soon thereafter so you don't want to wait too long.
A squealing belt is more often associated with the serpentine belt in your engine because that is a smooth belt and when it begins to show signs of stress then a squealing sound is more common to that. However, your timing belt may also make intermittent squealing noises. Unlike the ticking sound it makes when it fails, these sounds will not be continual and will probably only happen at certain times. Most often it will occur when you're accelerating or braking. There's also a chance you might hear this when you're idling.
As we said, the squealing noise could also be indicative of a problem with the serpentine belt so you'll need to look at some of the other symptoms of a bad timing belt to be sure that this particular noise is indicating a problem. The best thing you can do is try for a visual inspection though to see if your timing belt is in poor condition. Unfortunately it's usually pretty hard to get in there and get a look at it, so combined with some of the other symptoms that may be what you need to use to determine whether it's time to have your timing belt checked out by a mechanic.
Other Signs and Symptoms of a Bad Timing Belt
If the sounds being produced by your timing belt are not clear or you're not 100% sure if it's the source of the problem then there are some other signs and symptoms you could be on the lookout for it to let you know you're having a problem with the timing belt.
A typical timing belt will only last between 60,000 miles and about 105,000 miles. You need to refer to your owner's manual to know for sure how long yours is expected to last. Replacing the timing belt is routine maintenance that any driver of a car with a timing belt should expect to do at some point, so you can’t hope for one of these to last the life of your car, unfortunately. It's possible that a timing belt could last you as much as 120,000 miles and there's even been reports of some lasting 200,000 miles but those are rare cases and you can never plan on that working out for you.
One of the more common symptoms of a failing timing belt is when your engine misfires. If the belt is wearing out and slipping on the gears that it is attached to it will throw the timing of your entire engine off. That means your fuel and air mixture might not be injected into the cylinder at the right time or the spark might not occur at the right time causing that cylinder to misfire on you. Not only can engine misfires cause damage to your engine over time, they greatly impact the performance of your vehicle. Consider that if you have a four-cylinder engine and one of the cylinders misfires you are losing power equal to that cylinder which means you lost 25% of power at that moment. Every time your cylinder misfires, the same drop in power will occur.
If your timing belt is broken then your engine simply can't start at all because there's nothing to align the crankshaft and the camshaft. Typically the timing belt will break while you're driving which is very dangerous, so if it breaks just as you tried to get your car started, preventing it from starting, this is actually a more beneficial outcome because it will likely prevent the serious damage that can occur if the belt breaks while you're in the middle of driving.
Loss of Oil Pressure
The timing belt in your vehicle is located above the oil pan and it's possible that the teeth on your belt can break off and actually fall into the oil pan. Over time they can collect in one spot preventing the oil from recirculating back through your engine which will cause it to lose pressure. This will also lead to your engine overheating.
Check Engine Light
A problem with your timing belt can cause the check engine light to show up on the dashboard of your car. Unfortunately, there are literally hundreds of different reasons why a check engine light may come on so you may have to rely on these other symptoms to help narrow down the problem for you if the light does come on.
Even though the check engine light is a very vague warning that doesn't alert you to the specific nature of the problem that caused it to come on of the first place, it does at least let you know that there is a problem. That means you can combine it with these other observable side effects in the symptoms of a bad timing belt to help you figure out what's going on.
If you do have a check engine light on your dashboard and you want a more specific diagnosis of the problem before heading to a mechanic to get them to do your inspection your best option is to use the same diagnostic tool that a mechanic would use to check out why the check engine light showed up on your dashboard. You've likely seen the mechanic using what is called an OBD2 scanner before, or an onboard diagnostic tool. It looks like a large cell phone or tablet and is usually in a bright yellow case, but not always. This is what a mechanic will plug into your car to test why a dashboard warning light came on.
Although the mechanic you go to probably has a very complex OBD2 scanner you can get a basic one on a site like Amazon.com for as cheap as $30. This will still be able to help you diagnose the problem so that when a check engine light comes on your dashboard you'll be able to know if it's the timing belt or something else under your hood that made it come on in the first place. It won't fix the problem, but it does tell you where the problem is, so you know what to do to get it fixed.
Cost of Replacing a Timing Belt
Unfortunately, the cost of replacing a timing belt in your car once it goes bad is a little overwhelming. This is one of the more expensive repair jobs that you're going to need to get done in your vehicle. Depending on the make, model, and year of your car you can expect to pay anywhere from $500 to as much as $2,000 to get a timing belt replaced in your vehicle. This is due to the fact that it's a fairly involved job to get to the timing belt which is located deep in your engine. The belt itself will cost $100 to $300 if you head to a site like Autozone.com. Unfortunately, although it is technically possible to do this job on your own at home if you're not a very skilled mechanic already then you may want to leave this one to the professionals. It's a difficult repair and takes a lot of time and effort to get done correctly.
The Bottom Line
Replacing a timing belt is something that most drivers want to avoid if for no other reason than it's going to cost a lot of money and take up a good deal of time to get done. However, if you don't get your timing belt replaced on a routine schedule before it goes bad, the potential consequences could end up costing you many thousands of dollars more. It's a bit of a catch-22 in that regard, but it's always best to err on the side of caution and get your timing belt replaced when you start noticing those ticking noises or any of the other symptoms we've mentioned.