It takes a lot of different parts to make your engine function properly. Thousands of different pieces that work together to produce the power to move your entire car. Among all the pistons, valves, hoses, and gaskets you have a number belts as well that keep everything functioning. It's likely you may have heard of some of these before, and in particular your serpentine belt and your timing belt. And while it's good to know that you have them in your engine and you need them for your car to function properly, not everyone is aware what the difference between the two is and what they do to keep your engine functioning properly. Let's take a look at the difference between the serpentine belt and the timing belt, and also whether or not your vehicle even has a timing belt.
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What is a Timing Belt?
Some people may use the term timing belt and serpentine belt interchangeably. This is definitely not correct as the timing belt has a very distinct function from the serpentine belt in your vehicle. Your timing belt connects your crankshaft to your camshaft in your engine. The result of this is that as your crankshaft rotates the camshaft rotates along with it in synchronisation. This is of vital importance to the functioning of your engine. The camshaft rotating allows the valves to open and close. As the crankshaft rotates, the pistons will rise in the cylinders. The combustion reaction then forces the pistons back down again which keeps the crankshaft rotating.
If your camshaft isn't perfectly synchronized with the crankshaft, then your valves will not open at the correct time which means the pistons will crash into them and cause some serious damage inside the engine of your vehicle.
As the name suggests, the timing belt is the essential part of maintaining your engine timing to ensure that everything happens when it's supposed to. The functioning of your engine is based on precision timing. The pistons must rise at the exact right moment, the fuel injector must spray the fuel at the exact right moment, spark plugs must spark at the exact right moment to create the combustion reaction to force the pistons back down again. All of this happens in sequence through all the cylinders of your engine many times per minute. If anything is thrown off, then your engine could misfire or fail completely on you.
Timing Belt vs Timing Chain
It's worth noting that not every car has a timing belt in it per se. Some vehicles have a timing chain in them which performs the same function but, unlike the timing belt, this is more like a bicycle chain and it's made of metal. Timing chains are much more durable than timing belts and don't require the same kind of maintenance that a timing belt does. The timing belt only has a limited lifespan and will need to be replaced at around 60,000 miles to 100,000 miles or so. It's best to check your owner's manual to find out for sure how long it will last.
If you have a newer vehicle, there's a good chance you have a timing chain rather than a timing belt. Timing chains don't usually need to be replaced unless something has gone wrong with them. Which is to say it's possible a timing chain could fail on you, but they are meant to last the life of your vehicle. It would not be unusual for a timing chain to last 300,000 miles in a vehicle.
Signs of a Bad Timing Belt
When your timing belt starts to go bad on you there are some signs you can be on the lookout for to let you know that you're going to have a problem. As we said, when a timing belt goes bad the result is that your camshaft and your crankshaft will no longer be synchronized. That can spell catastrophic engine failure if it happens while you're on the road. The moment your timing belt breaks you will have no time to react because it's such a fast process. Your camshaft will stop rotating, your pistons will rise and hit the valves in your engine, and you could suffer damage to the valves, the cylinders, the pistons, the head gasket, and more. If it's bad enough you may end up with damage that costs in excess of $4,000 to repair.
Before that happens, there are some signs to let you know that your timing belt is beginning to fail.
Ticking Noise: One of the most telltale signs of a problem with your timing belt is a ticking noise that it will produce when it starts to fail. This will be a very fast-paced and repetitive ticking caused by the teeth on the inside of the belt that are meant to grip the camshaft and the crankshaft wearing down and even breaking off at some point.
Engine Misfires: If your belt is wearing out and has stretched out of shape somewhat, that will cause the timing of your engine to be off. This can manifest in the form of engine misfires. As we stated earlier, the timing in your engine is very precise. If your timing belt isn't functioning properly then the valve will not be opening at the right time for the pistons to rise and the spark to ignite the air-fuel mixture in the combustion chamber. If the combustion reaction doesn't happen in one of the cylinders, then the result is what's called an engine misfire. This causes a severe drop in engine performance as you can imagine.
Engine Not Starting: If the timing belt breaks at the moment you attempt to start your car, your engine will not be able to start as a result. In the grand scheme of things this is actually a better result than the timing belt failing as you're driving because if it happens while you're driving it could cause serious damage to your engine. This way, at least, you are not going to have to endure the massive repair bills from the engine and will only have to deal with a broken timing belt.
Cost of Replacing a Timing Belt
Although a timing belt itself is not an overly expensive piece of equipment and may often cost between $50 and as much as $300 for a new one, the repair of a timing belt can be extremely pricey. Replacing a timing belt can cost anywhere from $500 to as much as $2,000. This is because the labor involved in the repair is fairly intensive. Getting access to a timing belt requires a lot of work and will typically take a skilled mechanic several hours to accomplish.
The process of getting access to a timing belt is so complicated that many mechanics will also replace some other parts at the same time while they're in there simply because it's a time and money saver. Most specifically your water pump will generally be replaced along with your timing belt since they both have a similar life span and they're located right next to each other.
What is a Serpentine Belt?
The serpentine belt in your engine is responsible for allowing several different parts under your hood to function properly. The belt itself gets its power from your engine. One end is looped around a pulley at the end of the crankshaft in your engine which is constantly rotating while your vehicle is running. From there the serpentine belt loops around a number of different accessories inside your vehicle. This includes things like your alternator, your air conditioner compressor, your power steering pump, your water pump and more. In fact, this is why the serpentine belt gets its name. Because it snakes through all of these different components in your engine.
As the crankshaft in your engine rotates it causes the serpentine belt to spin. The spinning of the serpentine belt around that pulley in turn rotates around all of the components and provides them with power so that they are able to function properly. If your serpentine belt were to break, then there would be nothing powering numerous accessories in your vehicle and you would lose functioning in all the things that we mentioned.
Signs of a Bad Serpentine Belt
Because your serpentine belt powers so many of your accessories, you'll have a good indication that it's not working properly any longer when your accessories fail as well. Because of that, if you find that your air conditioning and your power steering failed at the same time, you may want to look at your serpentine belt. In addition, these are some of the other symptoms to let you know that your serpentine belt is not working properly.
Dead Battery: If the power in your car dies suddenly while you're driving, you may want to check your serpentine belt after checking to make sure your battery is still hooked up properly. The reason for that is because your serpentine belt powers your alternator. When your alternator fails, it's not able to charge your battery any longer.
Engine Overheating: Because your serpentine belt provides power to the water pump, when it fails the water pump will not be able to help keep your engine cool any longer.
Squealing Sounds: This is the most prominent symptom associated with a bad serpentine belt. When it starts to fail it will produce a high-pitched squealing sound that is pretty unmistakable and also very annoying. It's possible you can fix this by just making sure it's aligned properly, but it may also indicate that the belt is damaged to the point of almost breaking.
Visible Cracks: It's always a good idea to perform a visual inspection of your engine and the various components on a regular basis. When you check out your timing belt, look for cracks or breaks in the belts. If you're noticing any then that's a clear indication that your belt is wearing down on you and it's only a matter of time before it breaks entirely. When you can see cracks already formed, you should go get a replacement belt as soon as you can to avoid further problems down the road.
Cost of Replacing a Serpentine Belt
When your serpentine belt fails in your car, it's a bit of an easier job to repair this than it is when your timing belt fails. A serpentine belt has a lifespan of around 50,000 miles and, like a timing belt, it can wear out, break, and slip off while it's doing its job. When that happens, you can expect that you're going to have to pay about $100 to $200 to get it replaced by a mechanic. That's a remarkable drop from the cost of a timing belt, and it's mostly because accessing your serpentine belt is pretty easy. In fact, this is something you could likely handle on your own if you make sure you look up exactly how your serpentine belt is laid out in your engine so that you are replacing it correctly. You can buy a new serpentine belt for between $25 and $75 usually.
The Bottom Line
Knowing the difference between the various parts under the hood of your car and how they function to make the entire vehicle move is a tall order for many people. Mechanics can spend years learning everything there is to know about the ins-and-outs of a car engine and how it all works. Most of us only understand a fraction of how the engine makes our car work and what to do when something goes wrong. However, the more you know about your engine the better off you'll be in terms of understanding when things go wrong and knowing what needs to be done to fix it. This is better for you in terms of allowing you to maintain your vehicle more efficiently, and it also ensures that you're less likely to be taken advantage of when you do have to go in to a mechanic to get things fixed. It never hurts to know how your timing belt and your serpentine belt function, where they're located in your engine, how to tell there's something wrong with them, and what you need to do to keep them working properly.