Home Diagnosis and TroubleshootingEngine Problems Serpentine Belt – What Are The Symptoms Of A Bad Belt?

Serpentine Belt – What Are The Symptoms Of A Bad Belt?

by Jordan Harris
Serpentine Belt

Have your serpentine belt started squeaking lately and you are looking on learning the serpentine belt replacement cost? Аnd you also want to know what serpentine belt tool you can use to do this job? If this is the case, then you are at the right place because there will be a lot to cover on this topic.

Having a problem with the belts is one of the most annoying things that you need to fix. They produce weird noises and cause a lot of headaches. It doesn’t matter if it’s a timing belt or a serpentine one. They all squeak and rattle when they age and this can be a really annoying thing to deal with.

What is worse is that this problem is also dangerous for you and your vehicle. Why I’m saying this? Well, because it’s true. If it breaks you will be left without all of your accessories and this could be a real headache for you as a car owner. That’s why you need to dive deeper and study this problem and the symptoms.

But we are going to help you out with that. First, we will learn what is a serpentine belt. Then we will learn more about the serpentine belt diagram and we will compare it with the timing belt and what are the main differences between the two.

Later on, we will cover the symptoms and how to replace them. And normally, the serpentine belt replacement cost. Lastly, we will answer some common questions. So, if you want to learn more, follow along.

What Is A Serpentine Belt

So what is this belt in general? Let’s discuss some of the basics before we dive into more complex topics like the serpentine belt replacement cost and how to diagnose a bad belt.

This will be quite useful for beginners who are not into cars and want to learn some of the basics when it comes to this stuff. If you are feeling like you have the knowledge, you can move to the symptoms. If not, keep up with us for a bit.

This serpentine belt is also known as a drive belt or accessory belt. The main role of the drive belt or accessory belt is to power all of the accessory units in your car. And as you probably know, there are a ton of them.

Namely, the power steering, water pump, alternator, AC system. All these components need something to power them up in order to work. If there is not something that will make them work, they will not function at all. And the thing that spins these components is the drive belt.

The drive belt powers every component that needs power. And for this, you will need a serpentine belt diagram to understand how this belt is mounted properly on your car. But more on that in the following chapter.

What is important for you is to know what this component is and its utmost cruciality when it comes to proper engine work. Without this belt, your car will not be able to do anything.

The engine will shut off since the alternator is not working and it could potentially overheat. So, beware of this stuff. More on the symptoms later. Now let’s discuss the serpentine belt diagram.

Serpentine Belt Diagram

Now let’s cover another important topic and that is the serpentine belt diagram. As you know, in each car these belts are routed differently. Meaning that you will need a specific diagram for you to be able to route this belt on your car.

It is of key importance for you to learn more about the serpentine belt diagram specific for your car if you want to mount this belt the right way and not end up scratching your head of where everything goes.

Since cars can be quite complex when it comes to the routing of this belt and sometimes they can include even two belts. So, before you do a replacement, the best thing you can do is to take a lot of pictures of the engine with the belt on. Doing this will make sure that you don’t make a mistake.

Also, if your belt snapped, you can just go online and do a search “serpentine belt diagram + your make and model”. There are a ton of useful results on basically any car out there. So, don’t be afraid to consult yourself online when it comes to looking for a diagram for the routing of your drive belt.

You need to find solutions for your problems very quickly if you want to be a competent mechanic. And you need to develop your mindset and also improve your skillset when it comes to this stuff. Research first, replace the belt later after you did thorough research on that specific topic. Now let’s discuss another important thing when it comes to the serpentine belt.

Serpentine Belt VS Timing Belt

Now let’s cover another interesting topic and that is the topic of serpentine belt vs timing belt. Many people are confusing these two types of belts and think that they are the same. Which are actually not in reality.

The serpentine or also known as a drive belt is a belt that powers the accessory units in your car. Like the power steering, AC, water pump, alternator, etc. Meaning that this belt is not a timing belt.

The timing belt on the other hand has a different role. This role involves keeping the timing of the engine in check. Without proper timing, your engine will stop working.

Not all engines have a timing belt. Some of them have timing chains. Also, timing belts and timing chains only have interference engines. Meaning that the camshafts are mounted on the top of the engine. Then the timing belt makes sure that the timing of the valves and pistons is correct.

The timing belt is also hidden behind a plastic cover which is known as the timing cover. Unlike the drive belt that is not hidden.

Also, they are visually different. The timing belt has teeth. While the drive belt usually does not. Overall, that is everything you need to know when it comes to serpentine belt vs timing belt.

What Makes This Belt So Important?

Now let’s see what makes the serpentine belt so important? Well, to be honest, there is a lot of things that make this belt important.

Basically, without this belt, your car will not produce electrical current from the alternator. And as we all know, the alternator is the component that produces electricity. This electric current then powers up the spark plugs and makes sure that the combustion is performing well.

If the alternator isn’t powered up, your car will basically be left without electricity, resulting in an engine stall. The components will drain the battery. And when there is not enough juice in the battery, the car will stall completely. Now you see how important this belt is.

Another thing is the water pump that is circulating the coolant inside and outside of the engine. It is powered by this belt as well. If the belt isn’t there, the car could potentially overheat because there will be no coolant circulation.

Not to mention the power steering that will not work if your belt has snapped. The car will not be drivable and you will experience a lot of trouble steering the vehicle.

There are a ton more reasons that make this belt so important and you need to pay the serpentine belt replacement cost. But now let’s move to the symptoms of a bad belt. Let’s learn what are the possible signs that tell that your belt needs replacing.

Symptoms Of A Bad Serpentine Belt

Now before we dive into the diagnosing and the serpentine belt replacement cost, let’s cover some of the basic symptoms that you could experience when it comes to this issue.

Serpentine Belt

Knowing the symptoms will make a lot easier the diagnosing process as well as prevent the belt from completely snapping. So, if you want to learn more, follow along.

1. Squealing Sounds

The first symptom of a bad serpentine belt that you will notice is the squealing sounds that will develop when this belt is worn out.

These sounds can be really annoying and can literally piss you off. That’s why you need to sort them out as soon as possible. Unless you want your belt to jump or snap, in some more extreme cases.

The squealing sounds are a dead giveaway that your belt needs checking. Even though, sometimes these noises are not caused by a bad belt but in fact by a bad idler pulley or a belt tensioner.

Locating the cause of the squealing sound is key if you want to avoid possible problems with the belt snapping and you looking for serpentine belt replacement cost.

2. Visible Cracks

The second symptom that you are going to notice is the visible cracks on the belt. Worn-out belts usually develop a ton of cracks on them.

So, doing a close inspection and checking out the condition of the belt will be quite useful for you if your belt needs replacing.

The most important place for you to check would be the inside of the belt. This is because this is the place where belts crack. See if there is tension on the belt as well. Performing this work will basically help you diagnose the issue.

Cracks and loose tension are clear signs that you need to learn the serpentine belt replacement cost.

3. Overheated Engine

The second symptom that indicates that you need to look for serpentine belt replacement cost is engine overheating.

The engine will tend to overheat if you don’t react whenever the belt has snapped and the engine doesn’t receive enough power from the accessories. The water pump will not spin and overheating is imminent if you drive the car like this for a while.


The car will eventually overheat and the engine will shut off. The damage to the engine in this situation can be severe. The head gasket could burn and coolant and oil will mix. Not to mention that the engine head can crack. Overall, bad situation. Now let’s move to the next symptom.

4. No Power Steering

Another symptom that indicates that you need to learn about the serpentine belt replacement cost is the loss of power steering.

As you probably know, the power steering pump is powered by this drive belt that drives the energy from the crankshaft to all of the accessories.

So, if you suddenly lose your power steering, it might be because of a bad power steering pump. Or possibly because your drive belt has snapped. Your best bet, in this case, will be to stop the car immediately and prevent the engine from overheating since as we learned before, this belt also powers the water pump and the other accessories.

Whenever there is a loss of power steering, it could be two things. Either the power steering pump has failed, or possibly the belt has snapped. But how you can diagnose a bad accessory belt?

Well, that’s what we are going to discuss next in the article where we will learn more about this process and how it is tackled.

How To Diagnose A Bad Belt?

Now as we covered the symptoms of a bad serpentine belt. Let’s now move to other topics and learn more about the diagnosing process. How you can tell if you are dealing with a bad belt on your vehicle? What is the tell-tell sign that this belt has to be replaced as soon as possible?

Well, the first thing you can do is to perform a visual inspection and see if the belt is in good condition. A little peek under the hood will tell a lot about this belt and its condition.

Check the belt for play and see if it’s loose. If it is, this might be the reason for the squealing sounds that you hear. This looseness is basically telling you that you need to tighten the belt tensioner or possibly replace a pulley on some component if it’s broken and has play in it.

Observing the pulleys will give you a good representation to see if there is a pulley that has play in it. If there is a pulley that wiggles, then this needs sorting out.

Also, see the condition of the belt. If there are chunks missing from the inside of the belt and also if there are visible cracks, then this is a clear sign that you need to replace it with a new one.

Replacing it will be a complete lifesaver for you as a car owner because you will avoid the possible snapping of this belt and avoid being left without the accessory units on your car. Now let’s learn how to replace the belt with a serpentine belt tool. And after we will cover the replacement cost.

How To Replace Serpentine Belt

Now let’s discuss more on how you can replace this belt alone using common tools? As you probably know, this is not a timing belt. So, replacing this belt is really straightforward.

The only thing you will need will be a serpentine belt diagram to know where everything goes. Or, take a lot of pictures along the way to make sure that you don’t make a mistake while replacing this component.

For this job, you will only need a new belt, a ratchet, also known as a serpentine belt tool as well as a new tensioner and idler pulley.

Replacing these pulleys and tensioners is essential because you will have a lot of troubles along the way if you don’t. They could fail if not replaced on time and the belt could jump or snap. So, replace them when you do the accessory belt like in our case.

For replacing these components you will need only a serpentine belt tool. Also known as a ratchet. This ratchet is basically a lifesaver when it comes to these problems and sorting issues like these.

Your task will only be to loosen up the tensioner with the ratchet and that will be it. Release the tension of the belt and the belt will come off pretty easily.

The next thing you will need to do is to replace the tensioner and the idler pulley. After you replace these units, then you will need to place the new belt in the same manner based on your diagram.

Then you are good to tighten the tensioner up to spec and you will be good to go. If anything squeals, make sure that you tighten it again. Then you will be good to go. Now let’s cover the serpentine belt replacement cost.

Serpentine Belt Replacement Cost

But what does the serpentine belt replacement cost? How much you can expect to pay for sorting this problem on your car? Is it really that expensive? Well, actually it’s not that expensive to sort it out.

The parts alone will cost you somewhere between $70 to $120. Which is not a lot of money. Considering that this part is replaced every 60,000 miles, this isn’t that scary at all.

Serpentine Belt

What is expensive though, is the labor for sorting this problem. The labor might cost you between $100 to $150. But if you have a ratchet in your garage, you can replace the belt and the pulleys on the cheap and spend zero dollars on the labor. Now let’s answer some common questions concerning this.


In this article, we have covered quite a bit when it comes to the serpentine belt. First, we covered what this belt really is and what is its main role and that is to drive the accessory components in our vehicles.

Then we covered how you can diagnose and sort out the problem quickly and effectively. Lastly, we covered the costs that are involved in this type of work.

Serpentine Belt F.A.Q

Now let’s answer some common questions concerning this belt. These are the most common things that person who is facing this problem is asking themselves and in them, you will probably going to find the solution for your problem.

What Is A Serpentine Belt

A serpentine or accessory belt is a belt that powers up accessory units on your car like the AC, power steering, water pump, and alternator. This belt is driven by the crankshaft on your vehicle and this powers all these different accessories and makes them work as they should.

How To Change Serpentine Belt

Replacing this belt is relatively easy. For replacing this belt you only need a ratchet. The first thing you need to do is to remove the tension on the tensioner, then the second thing you will need to do is to replace the pulleys that are holding the belt and place the new belt in and tighten the new timing tensioner up to spec.

How Much Is A Serpentine Belt

Serpentine belts on average cost about $70. But this price can go up to $120. Depending on the make and model your car is. The more expensive car, the more expensive this belt will be. So, beware of this before purchasing a vehicle. Expensive vehicles are more expensive to maintain.

What Happens To A Car When The Serpentine Belt Breaks?

When a serpentine belt breaks, you will experience loss in power steering, the engine will overheat, you will lose the AC system, the battery will drain and the engine will eventually stall. So, whenever you notice something strange, it is very important for you to act quickly and check if the belt has snapped. If there is no belt. Then you will have to tow your vehicle to the nearest service center and have your serpentine belt replaced. It is expensive. But it is what it is. That’s why you need to replace the belt on time.

What Causes A Serpentine Belt To Break

The main cause for this belt to start braking is the age and the miles that are accumulated on it. The more miles the belt has on it, the bigger the chance for the belt to break and cause the failure of the accessories. That’s why it is best for you as an owner to focus more on the intervals when these components have to be replaced.

When To Replace Serpentine Belt

Replacing this type of belt is recommended to do every 5 to 6 years or after 60,000 miles. Both of these factors which are age and miles determine the life of the belt. So, replace it during this time frame and you will have no issues with it.

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