If all of a sudden, you hear a squealing noise coming from the front portion of your car and after a while, you noticed power steering is not reacting properly which could be a critical safety hazard, it means something is wrong with the serpentine belt – either it has got misaligned, broken, or is in poor condition.

Whatever is the case – your serpentine belt needs replacement.

Through this article, you will get to know in and out of the serpentine belt including – how it works, what are the elements that cause the serpentine belt to go bad, and what are the signs that indicate you of that serpentine belt is going bad.

This will make you more informed and help you avoid the things before it gets worse.

Let’s start with the basic of serpentine belt:

What is a Serpentine Belt

A serpentine belt is a pivotal part of your vehicle’s engine – also known as a drive belt, accessory drive belt, or fan belt which helps drive several crucial automotive components within the vehicle including the alternator, power steering pump, air conditioning compressor, and water pump.

The serpentine belt basically powers these components to ensure that the engine is running exactly the way it is supposed to be.

If this belt goes bad or snaps – it can damage the parts attached to it. Sometimes if you keep driving with a bad serpentine belt, it can damage the engine itself too, that’s why it is very important to do regular inspection of the serpentine belt.

How a Serpentine Belt Works

There is a simple mechanism works behind the working of a serpentine belt. The serpentine belt or drive belt is attached to the components – alternator, power steering pump, air conditioning compressor, and water pump via idler, tensioner, and pulleys which keep these devices connected the drive belt. When the crankshaft moves using the power obtained from the combustion process, it moves other components too attached to it via a serpentine belt.

This way, all components connected the serpentine belt moves along the belt. Thus alternator keeps supplying power to the devices, the power steering pump keeps running to drive hydraulic power steering, and water pump keeps running to cool down the engine. Thus it increases the overall efficiency of the engine.

7 Symptoms of a Bad Serpentine Belt

Driving a car with a bad serpentine belt can result in quite serious car problems. If it is overlooked or not replaced on time, it can cause severe damage to the vehicle’s engine. But the question is how you would know that the serpentine belt is failing or going bad, so you can take action timely.

So, here are certain signs and symptoms that will indicate the poor performance or bad condition of your vehicle’s serpentine belt.

1. Squealing Noise

Squealing noise coming from the engine area is the most common sign of a bad serpentine belt, this happens when either the serpentine belt is misaligned or has become loose.

The solution to this problem is to tighten the belt and align it properly. If still the squealing noise exists, then it only requires replacement.

2. Air Conditioning is Not Working

If suddenly the air conditioner of your vehicle becomes slower or stops working, this can attribute to a bad or broken serpentine belt.

However, there are many other things that can prevent the air conditioner from working but because the serpentine belt is the one that makes the air conditioner working, so there is a possibility that serpentine belt is the culprit that needs to be replaced.

3. Loss of Power Steering

If you notice a loss of performance in power steering, there is the possibility that the serpentine belt has failed or broken. However, this issue can also be caused by a faulty power steering pump or low power steering fluid.

So, before you check the serpentine belt, make sure the fluid is up to the level. If the pump and fluid level both are okay, then check the serpentine belt.

4. Increase in Engine’s Running Temperature

Since the serpentine belt drives the water pump, so if the serpentine belt fails or breaks, the water pump will stop working that leads to overheating of the engine.

Therefore, if you notice that engine is overheating, check the serpentine belt. If this problem is left unchecked, this can cause damage to the engine.

5. Cracks on Belt

You can visually inspect the serpentine belt if you notice any cracks, abrasions, or uneven rib wear it means it’s time to replace your serpentine belt. Delay in replacement can cause damage to the engine, so make sure you replace it as early as possible.

6. Degraded Battery Charging

If the battery charge is continuously getting lower, it means the serpentine belt has stopped running the alternator and without alternator’s charge, the battery will die and eventually, the car will stop running. For this problem, the only solution is to replace the serpentine belt.

7. Exceeded Mileage Threshold

The serpentine belts come with mileage threshold and according to it the serpentine belts typically last between 60,000 miles and 100,000 miles. So, if your serpentine belt has exceeded its mileage threshold, it means that it needs replacement.

What Causes a Serpentine Belt to Go Bad

1. Lack of Maintenance

This is the most common and obvious reason why would a serpentine belt has a problem. Over time, the serpentine belt can get cracked or frayed due to its continuous exposure to heat. A coolant leak can also cause the belt to slip or damage. Regular maintenance helps solved such issues before things get worse.

2. Higher Air Humidity

When there is a high amount of humidity in the air, the water vapors can settle down on the serpentine belt and can act as a lubricant for causing it to slip. If the belt gets slipped from its place, all of the accessories connected to it will stop functioning.

3. Damaged or Misaligned Pulleys

However, the pulleys are made of very durable material but its constant exposure to heat and consistent rotating behaviour cause damage to it. When ribs on the pulleys get damaged, it causes a serpentine belt to wear out. Even if you replace the serpentine belt but damaged pulley again cause it to wear out.

If the pulleys are not aligned properly, they can restrict the belt from rotating in a straight line which again causes damage to the belt.

4. Damaged Devices (Alternator, AC Compressor, Power Steering Pump etc)

If any of the devices connected to the serpentine belt is damaged or not working properly can cause a serpentine belt problem.

For example, if the alternator is not working due to a damaged bearing, the rotor would also not rotate properly and this will affect the pulley’s performance resulting in causing damage to the belt. The same thing will happen in the case of each device driven by the belt.

The timely maintenance can help avoid serpentine belt problems.

A loose drive belt tensioner

A loose drive belt tensioner can cause the belt to crack which will conclude to bad consequences such as overheating, a defunct electrical system and battery, or a disabled AC system. In such scenario, both serpentine belt and tensioner need to be replaced to resume the vehicle to its full efficiency.

Serpentine Belt Replacement Cost

Despite being such an important part of the vehicle’s engine, the replacement of the serpentine belt is pretty cheaper. The replacement cost will not exceed $200 no matter how difficult it was to locate this component.

The replacement cost will fall between $100 and $200 including labor cost and component cost. The serpentine belt will cost you between $25 and $80 and labor cost will vary between $75 and $120 and after this, service tax and fees will be added to the cost which will aggregate to the total cost.

The labor cost will vary depends on the ease of accessing the serpentine belt. If the belt is easily accessible, the whole replacement process will not take more than an hour and labor will charge you for 1 hour. But if the belt is located in a place which is hard to locate, it may take more than an hour and labor can charge you for two hours.

This is undoubtedly one of the cheaper components of an engine and replacement cost is also very meagre. You know that delaying its replacement can cause more damage to the engine so, it is better you replace this on time beofe causing expensive damage.

Can You Drive With a Bad Serpentine Belt

This is a very common question that hits our mind when it comes to a bad serpentine belt. With a broken serpentine belt, it would not be possible to drive the vehicle. if somehow you start the vehicle but it would be very hard to steer the vehicle.

But with a frayed serpentine belt, you may be able to start and drive the vehicle but if you keep driving with the bad serpentine belt, It can snap anytime and cause big trouble for you.

So, it is better you do not drive the vehicle with a frayed serpentine belt and tow the vehicle to the mechanic to get the thing right.

How Long Can You Drive with a Bad Serpentine Belt

With a bad or broken serpentine belt, you can’t drive longer as in a few seconds only you will start losing power steering, AC, and battery power and the biggest effect comes on the water pump that starts making engine overheated.

If you keep driving with the bad serpentine belt, you will only turn an inexpensive repair into a huge and very expensive repair that may cost you several thousand bucks. It is better you do not attempt to drive the vehicle unless the serpentine belt is replaced.


The information provided in the article has been derived from multiple sources as well as our own long experience with a varied kind of vehicles. We hope this article has made you more informed about this particular car part.

Whatever is the scenario, when it comes to the serpentine belts, the immediate replacement is the best thing you can do.