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Signs of a Bad Serpentine Belt - What Causes a Serpentine Belt to Break

Signs of a Bad Serpentine Belt – What Causes a Serpentine Belt to Break?

The life span of your car components depends on the material used in the making of these components. In addition, the component wear also depends on how rigorously you use them, which precisely tells what makes them damaged or broken. If we talk specifically about the serpentine belt, what causes a serpentine belt to break? This happens because of oil leaks, faulty filters, and reckless use of the components.

Even if the material is authentic, most of the serpentine belts last more than 50,000 miles, and very rare of them go beyond 100,000 miles. Generally speaking, no matter what type of car component you see, after a long time it gets out of work. This is why it is essential to maintain not only your vehicle but keep the essential components up to date so all the components remain in a good shape.

The serpentine belt is located in the engine bay and connects a number of components and pulleys there. A serpentine belt can cause the engine to cease or its damage can cause malfunction of the engine. This is why it is an important component of the engine to be taken care of.

If you don’t want to spend a lot on your engine, it is better to figure out the reasons and symptoms when the serpentine belt gets bad.

What causes a serpentine belt to break?

Everything can take a bold turn if hit hard by an external force, no matter what component. Here under are some of the factors that play actively in the breakage of the serpentine belt.

1. Associated Faulty Gears

A serpentine belt is placed in the engine of a vehicle and connects various peripherals like a water pump, alternator, air conditioning compressor, power steering pump, air pump, etc. Now suppose if any of these components get damaged or do not work properly, it automatically exerts extra pressure on the belt which makes a serpentine belt break.

More stress on a serpentine belt from the failed bearing inside the alternator can also break down an extensive pressure on the belt that causes it to damage. Having said that the faulty components can cause the serpentine belt to break, the alternator would be one of the culprits.

2. A Weak Belt

One of the components that keep running in the background in a vehicle is a serpentine belt. It keeps itself in motion from the moment you start the car until you stop it. Therefore, the serpentine belt needs to be made from materials that last a lifetime, they are called lifespans.

Back in the time, serpentine belts lasted not more than 50,000 miles as they were used to be made from Neoprene rubber. In the current times, newer ones can last up to 100,000 miles and even more. This is because they are made of Ethylene Propylene Diene Monomers (EPDM) rubber that has a guaranteed life of a lifetime.

So if your vehicle has driven 100,000 miles or over, it’s better to get your serpentine belt replaced before it gets broken down and you get into paying a high cost of repairing your engine.

3. Oil Leaks

Many times you become unable to understand what causes your engine to leak oil. You just notice one day that oil is tripping from your engine bay. If this malfunction gets neglected and the serpentine belt has soaked the oil, then certainly the belt will start slipping from the core and can be easily broken after some time. This is because when the engine gets hot, the oil in the engine bay and the surrounding gets hot too. The serpentine belt in the engine which is already soaked in the oil gets sticky and the engine debris will cause it to break in no time.

Here it is important to note that even if you replace a new serpentine belt and if the engine has leakage, there will be no use in changing a new belt. No wonder you will be needing to replace a new belt after a while again.

That being said, you need to find and fix the main source where the oil is leaking, then replace a serpentine belt.

4. Defective Hydraulic Belt Tensioner

Many cars in the current times have hydraulic serpentine belt tensioners. These tensioners are protected by a shock absorber to get them intact in their place. If the tensioner or the shock absorber gets bad, the pressure on the serpentine will increase significantly and would become the cause of serpentine belt breakage.

Before you install a new serpentine belt, make sure to find faults in the hydraulic belt tensioner. Otherwise, the belt may break again.

5. Misaligned Pulleys

Suppose when you get your car repaired by a mechanic last month didn’t align the pulleys in the engine back in their place efficiently. This also can become one of the reasons to squeal and break the belt. Misalignment of the pulleys can wear the belt quicker and faster.

Misalignment of the pulleys is hard to find. You can detect them just from the symptoms which include an unusual whining sound and increased wear on one side of the serpentine belt. You need to take your vehicle to the mechanic again to do a thorough check.

The right time to change a serpentine belt

As said, the current cars having a serpentine belt made of EPDM has a lifespan of 100,000 miles. As soon as you observe that your car is reaching the milestone, you should get your serpentine belt replaced. In addition, at times it may be possible that you need to replace your serpentine belt earlier than it is intended.

For example, for any of the reasons mentioned above, if your engine makes a loud noise, you need to replace it and install a new serpentine belt as soon as you can.

Replacement cost of Serpentine belt

Contrary to people’s belief, the cost of a serpentine belt is not too much, they are rather inexpensive compared to the other parts of the engine. The cost of the most expensive brand of serpentine belt is even below $80.

Although your mechanic may ask you to pay around $150 or more depending on the place and experience of the mechanic and another influencing factor (s). Therefore, an average total cost of replacing a serpentine belt would be between 150-250 dollars.

Signs of a bad serpentine belt

A broken serpentine belt can be tracked if your engine shows the following symptoms once you start your car.  These symptoms and signs can be different depending on the model of the car, peripherals of the engine, arrangement, and configuration of the vehicle.

  • Wining and noisy ticking sound from the engine
  • Engine overheating
  • Power steering, AC, or alternator did not work properly
  • Unable to start the engine
  • Belt showing cracks


A serpentine belt is one of the essential components of a car engine. It connects many peripherals and joins pulleys within the engine. This is why if the belt is broken down due to oil leakage, faulty peripherals, or any other reason, the engine faces severe outcomes. If the serpentine belt issues or damage is neglected, your engine will eventually suffer and you have to pay a hefty price to repair everything to get your car to work again.

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