If you've heard of a timing belt but aren't one hundred percent sure what it does, it can get a little confusing trying to figure out why it's important, how to know when there's something wrong with it, and what it cost to fix one when something goes wrong. That also makes it hard to determine if it's even bothering worth fixing, or if it's something you can put off for a while. It's definitely in your best interest to understand how your timing belt works, and why it's so important to the function of your vehicle. In the most basic terms, your timing belt synchronizes movement in your engine so that the valves open and close at the right time to allow your engine to work and power your vehicle. Let's look at that a little more closely.
How a Timing Belt Works
Your timing belt works by synchronizing the movement between your camshaft and the crankshaft in your vehicle. The camshaft is what operates the valves in your engine that let gasoline and air mix in your engine. The crankshaft moves the pistons up and down in the cylinders. Their movements need to be precisely timed, so that the air/fuel mix is injected into your engine at the exact right moment. If any part of the system is off, you're going to end up getting engine misfires and losing power in your engine, losing fuel economy, and in some cases you will simply not be able to get your car started at all if it's bad enough.
There's a potential risk of serious damage if your timing belt isn't working properly. If it slips off entirely for instance, you could end up having a catastrophic engine failure because the parts are no longer working in order. The camshaft and the crankshaft must be working and precise synchronisation to avoid serious damage.
As the name suggests, a timing belt is a rubber belt. It slips over gears that are found at the end of both the camshaft and the crankshaft. The inside, the part that is attached to the gears features rubber teeth that catch on the gears and allow the belt to rotate and turn with the camshaft in the crankshaft. There's a potential if something goes wrong for those teeth to wear down and even break off. If they're damaged or missing, your timing belt will not work properly, and that can throw your engine off.
Timing Belt vs Timing Chain
As we said, a timing belt is made from rubber. It's meant to operate in the high temperatures of your engine, and of course it is a high-performance piece of equipment. Even though it's just made of rubber, a new timing belt could cost you between $100 and $200 just for the part.
A timing chain performs the same function as a timing belt but, as the name suggests, the timing chain is made from metal. Timing chains were the norm in older vehicles. In the 1970s in particular, auto manufacturers were looking at ways to save costs during the oil crisis so that the price of vehicles could be kept down. During this time the timing chain was replaced with a timing belt in many vehicles. Rubber is cheaper than metal and was easier to produce. The rest is history.
A number of modern vehicles, particularly more high-end vehicles, have begun switching back to timing chains instead of timing belts. Timing chains can last much longer than timing belts and are not susceptible to the same kind of wear and tear because they're made of metal. They are more expensive, but the trade-off may be worth it in the long run.
Signs of a Bad Timing Belt
When your timing belt has gone wrong in some way, either the teeth have begun to wear off or break apart, or the belt is slipping from the gears, you're going to notice some prominent issues in the way it performs. Be on the lookout for these symptoms and they'll let you know that you need to have your timing belt looked at.
Engine Misfires: Although there are a lot of things that could end up causing a misfire in your vehicle, a problem with the timing belt is one of the more common ones. Misfires occur when the cylinders open or close at the wrong time in your engine and the air and fuel mixture doesn't get injected at the precise right time to allow for a combustion to occur. When this happens, the valves and cylinders open, and when there should be firing there is not. Thus, a misfire.
In a 4-cylinder engine, this is going to cause your engine to lose 1/4 power overall because one of the cylinders was not able to perform its function. The rest of the engine is forced to compensate, and you end up losing power. This also ends up costing you in a fuel economy because you'll be spraying fuel that doesn't get ignited properly.
Frequent engine misfires can end up causing serious damage to your engine, including warping of the valves, cylinders, and pistons.
Rough Idling: Like engine misfires, rough idling is a problem that can have a number of root causes but a problem with your timing belt is certainly one of them. When the teeth come loose from the timing belt they can fall into the gears, which can cause your car to jerk and vibrate even when you're sitting at idle and not driving.
Noises: As an attentive driver you always need to be on the lookout for unusual sounds coming from your engine. You know how your car is supposed to sound when it's driving, so when something unusual happens and you're hearing and you sound you know that you should look into it further to find out what it is. When there's an issue with your timing belt, usually related to the rubber teeth wearing down and breaking off, it causes the belt to run on evenly between the camshaft and the crankshaft. That ends up creating a ticking sound as it moves between the years. It will be a fast-paced sound, and definitely one that's out of the ordinary compared to how your vehicle normally sounds.
Engine Not Starting: If the timing belt has completely stripped off, or broken, then there could be no synchronization between the camshaft to the crankshaft. That means your engine will not be able to start at all, because the combustion cannot occur. In this case when you turn the key in the ignition or press the starter button, you'll hear the starter motor attempt to get the vehicle started, but the combustion reaction will not take place in the car cannot start. In this case one of the only things you could do is call a tow truck and take your vehicle to a mechanic.
Oil Pressure: If pieces of the rubber teeth from your timing belt are broken off and fallen into the oil pan, that can end up causing serious issues with your oil pressure. The oil pan collects oil and allows it to recirculate back through the engine to keep it lubricated. Those rubber teeth end up clogging the system preventing the oil from draining out properly and then recirculating. That means you'll have low oil pressure, and also potentially an overheating engine and problems with parts grinding together without oil in there to lubricate everything properly. This could be a very serious and costly problem to repair if it goes on for too long.
Timing Belt Replacement Cost
One of the most frustrating things about dealing with a timing belt issue is the cost of repairing it. A timing belt seems like such a simple piece of equipment in your vehicle but the cost of repairing one can be extremely expensive. Many first-time drivers who have never dealt with this before are often surprised to find out that the cost of having a timing belt repaired can range anywhere from $500 up to $2,000 or more.
Repair costs are always inconsistent unfortunately, and very much depend on a number of factors. Where you live is one of the big concerns in terms of what you're going to pay for repairs. Repair costs reflect the city and state you live in more often than not, such that repairs in a city like Chicago are probably going to be more than repairs in a small town in Rhode Island.
By the same token the make, model, and year of your vehicle also has an effect on the cost of a timing belt repair job. In vehicles where it's harder to get to the timing belt, it's probably going to cost you more because more labour is required to get in there. Even in the simplest vehicles, getting to you your timing belt is a labor-intensive project which is why it costs so much.
Because of where the timing belt is located, essentially at the heart of your car's engine under the hood it requires a lot of time and effort to get to it. This is why many mechanics will also replace the water pump in your vehicle at the same time if they're taking out a timing belt and putting a new one on. The water pump is also hard to get to, and it has a lifespan that is fairly similar to that of a timing belt. If one fails, it makes sense to go ahead and replace the other one.
Can I Replace My Own Timing Belt?
This is one of those questions that has two equal and opposite answers. Of course, you could replace your own timing belt, you could technically repair any part of your car's engine if you are so inclined. This is a more advanced repair that most people have tried to take care of at home, however. If you are new to DIY auto repair at home, this is probably not the best job to start with. That said, if you are comfortable with working under the hood, you feel confident in your abilities, then you could definitely give this a try at home. It could end up saving you hundreds if not thousands of dollars if you can get it done properly on your own. It's all a matter of how confident you are in your own skills, and your ability to get it done.
As we said, this is an advanced repair job, but if you do feel like it's a task that you can take on, then there are a number of ways that you could go about getting it done. We recommend checking out a video like this one which can show you step-by-step how to get the job done. It's often much easier to follow along when you're watching a skilled mechanic get it done who can show you the process step by step, and you can go back and review each step if you feel like you've missed something or aren't sure how to go about it.
The Bottom Line
If the timing belt in your car fails, your car is going to fail as well. If you have something called an interference engine, when your timing belt fails the pistons are still going to hit the valves in your engine destroying them and causing thousands of dollars worth of damage. If this is bad enough you may need to completely replace the engine. That's definitely something you don't want to do.
When you notice any of those telltale signs that there's something wrong with your timing belt, it's definitely in your best interest to get it taken care of as soon as possible. Either take it in to get a skilled mechanic to take a look at the problem or try your hand at repairing it yourself if you feel like you're up to the task and have the right parts that you need. I always make sure you check your owner's manual or on a site like AutoZone which can tell you exactly what kind of timing belt you're going to need to fit your vehicle.