Bad Serpentine Belt Symptoms/ Drive Belt : All that You Need to Know

There is more to that functional engine that makes your vehicle move. There are a host of other car parts that work in tandem to get your car moving. One such vehicle part is the serpentine belt. This is a vital but less discussed vehicle component, which can bring your vehicle to a halt if it is faulty. Given its significance to your vehicle’s performance, you must be able to recognize bad serpentine belt symptoms. If you are looking for an answer to the question, does the serpentine belt affect the transmission? You might want to continue reading because the rest of the article will focus on many things that you need to know about serpentine belts.

What is a Serpentine Belt?

Older vehicles have engines with several V-type belts (more on that later), with each of the belts powering at least one component. The downside of this system is that there is always a need to maintain and replace several belts. The introduction of the serpentine belt changed that.

what causes a serpentine belt to break

The engine component known as the serpentine belt is a long, winding belt (hence the name “serpentine) that connects several accessories to the main drive pulley. The engine turns this pulley, so when you turn your vehicle’s engine, the crankshaft spins, and this motion turns the pulley. As the pulley rotates, the serpentine belt moves and powers the vehicle’s accessories connected to it: the power steering pump, the radiator fan, the alternator, and the air conditioning compressor, among others.

The serpentine belt is situated outside the engine block and is relatively easy to identify. It is a black, ribbed,snake-like belt on the outside of the engine block. It coils on other vehicle components and is continuously turning for as long as the engine runs.

It can either be tensioned automatically or manually; however, if you drive a modern vehicle, you are more likely to find an automatically tensioned serpentine belt on your engine. The automatic tensioner serves to keep the serpentine belt at the right tension as it always applies the right amount of tension to the belt. Without the right tension, the possibility of the serpentine belt slipping and disengaging from the pulley increases. You don’t want that to happen because the engine will stop running after key components powered by the belt no longer work.

Although the average serpentine belt is built to last, how long your serpentine belt lasts depends on the material it was made from. There are the Neoprene rubber belts and the Ethylene Propylene Diene Monomer rubber which are built to last about twice as long as the Neoprene belts. Regardless of the material used, at one point, you will need to replace your serpentine belt.

There are several reasons why you might need to replace your serpentine belt. The belt might not be well-adjusted on its pulley, it might be contaminated by fluid or just worn out from frequent use. Regardless of the reason, serpentine belts almost always let you know when they are about to fail. Detecting symptoms like bad serpentine belt sound or power steering noise and promptly acting on them will save you a lot of problems with your car.

Bad Serpentine Belt Symptoms

A bad serpentine belt can cause a lot of damage to your vehicle. So what happens to a car when the serpentine belt breaks? A lot of things. Here are some of the more common signs of a bad serpentine belt that you should look out for and resolve as soon as you can:

bad serpentine belt tensioner symptoms

Squealing Sounds

 One of the more apparent signs of a bad serpentine belt is when you hear sounds around your vehicle’s front area. This is often an indication that your serpentine belt is poorly adjusted and is slipping. It could also occur after the undercarriage of the vehicle has been washed. Usually, the squealing sound stops after a bit. However, sustained squealing sounds in the car’s engine area could well indicate that the belt is damaged. In such an instance, this high squealing sound is most noticeable when the vehicle ascends an incline. It is one of the bad serpentine belt tensioner symptoms that is hard to ignore.

Steering Problems

If your vehicle has Variable Assist Power Steering, then the serpentine belt is responsible for the power steering system’s functionality. The serpentine belt is responsible for powering the power steering pump so that it functions properly. Without power steering, it becomes difficult to steer your vehicle smoothly. You have to struggle with the steering before you can control the vehicle.

No Air Conditioning

The serpentine belt powers the AC compressor, so when there is a problem with the serpentine belt, your vehicle’s air conditioning will be affected. That is not to say that a failed serpentine belt is responsible when the AC is on, but there is no cool air from the air vents. Checking your serpentine belt is a great place to start if the situation arises.

An Overheating Engine

The engine is cooled by the water pump. Since the serpentine belt also powers the water pump, an overheating engine is another symptom that you should be wary of. When there is a problem with the serpentine belt, the water pump is not powered so it cannot pump the water needed to cool the engine. Over time the engine begins to overheat and could get damaged if it keeps running without a functional water pump.

Damaged Serpentine Belt

This is one of the visual indications that something is wrong with your serpentine belt. Any damage to the serpentine belt is a symptom that the belt needs a replacement. Serpentine belts are sturdy and are built to run continuously for miles upon miles. After a while, the wear and tear of running for so long begin to tell on the belt. This wear and tear are what causes a serpentine belt to break.

 This shows via cracked, damaged ribs, abrasions, and rib wear on the belt. So carrying out a physical inspection of the vehicle’s serpentine belt is a great way to confirm if your serpentine belt is about to pack up.

Whining Sound

Whenever you notice a whining sound that increases and decreases according to the engine’s speed, there might be a problem with the serpentine belt. When the belt is pulled too tight, there is a possibility of putting too much load on the bearings of the pulleys connected to the belt. The whining sound is a result of an overloaded accessory pulley. It is one serpentine belt noise that indicates that there is an issue with your serpentine belt.

Poor Driving Experience

Vehicle performance issues can also indicate a problem with your vehicle’s serpentine belt because bad serpentine belt causes loss of power. Indeed a problem with an overheating engine, the air conditioning or the power steering are different symptoms that reduce your driving experience. When you notice a combination of issues like rough idle, flickering lights when you start the engine, dimmed headlights, and difficulty in starting the vehicle (which mostly points to alternator issues) you want to check the serpentine belt. So if you have searched for answers to the question, can a bad serpentine belt cause rough idle? The answer is yes.

Serpentine Belt vs. V Belt

Let’s compare both components.

Serpentine Belt V-Belt
It is bigger than the V belt and is only used in newer vehicles. You will only find one serpentine belt in a car and several accessories are connected to it for power. This belt is thinner and smaller than a serpentine belt and can be found in older vehicle engines where they are dedicated to one accessory at a time. There are often multiple V belts in an engine
The serpentine belt is less complicated and easier to handle given its multi-rib design that guarantees less slippage. The distance between the accessories is shorter, so the vehicle’s engine compartment is less clumsy as there are fewer components to deal with. Serpentine belts are generally easy to install and maintain.  It is a lot more complicated to manage the V belts, especially with how the accessories and pulleys are located around the engine. It can be challenging to negotiate so many components when a V belt has to be replaced.
You will need to change the brackets and pulleys to pull off a serpentine belt conversion. The V-belt has a deep V, which helps the belt stay longer on the pulley whenever there is a chance of it slipping. It is designed to fit in the grooves on the pulleys. Its small compact size also makes it great for vertical or horizontal orientations.
Serpentine belts are great for long distances since they can handle high RPMs V-belts are not designed to handle high RPMs, so they are not a good idea for long distances.
You don’t have to re-tension the serpentine belt all the time. All you need is an automatic tensioner that maintains the right tension at all times. V-belts need to be re-tensioned regularly.

 Serpentine Belt vs. Timing Belt

Serpentine Belt Timing Belt
The serpentine belt is vital to several engine functions since it powers a lot of engine components. It is designed to connect accessories like the AC compressor, the water pump, the power steering pump, and the alternator. This way, several engine components work in unison while the engine is running. The timing belt attaches the crankshaft in your vehicle’s engine to the camshaft. The timing belt is responsible for the timing in the operations of the pistons and the valves and cylinders. So any issue with the timing belt will prevent both components from working in tandem and ultimately hamper the vehicle’s engine’s proper functioning. This is one of the loose timing belt symptoms.  
The serpentine belt is obvious as it is looped around several engine components on the engine’s exterior. It is structured like a snake that twists and turns around different engine parts. On the other hand, the timing belt is located inside your engine, where it hooks into the gears.
As a result of its design and location, it is relatively cheap to replace your serpentine belt. Depending on your vehicle’s brand, model, and year and how you choose to replace your serpentine belt, the cost should be anything between $50 to $200. Timing belt replacement cost can be high because the timing belt is located within the engine, making it more difficult to access. Depending on the type of vehicle involved, the availability of the kind of belt, and the mechanics you hire, replacement costs for a timing belt can be anywhere around $300 to $500.
Serpentine belts have a snake-like form with ribs that allow them to attach to different accessories on both sides. Timing belts have little teeth that are designed to grip the engines’ crankshaft. You are likely to hear a timing belt noise when this does not happen. You can learn also the Timing belt vs Timing Chain 

Serpentine Belt Replacement Cost

So how much does it cost to replace a pulley and serpentine belt? The cost of replacing a serpentine belt depends on the make, model, and year of your vehicle on the one hand. Where you choose to get it done also matters, there will be a difference between serpentine belt replacement cost firestone and serpentine belt replacement cost Valvoline. Similarly, replacing the serpentine belt in your garage is cheaper than having a professional do it for you.

A significant part of the costs of replacing serpentine belts goes to labor costs. The typical serpentine belt costs around $25 to $75.If you opt to do it yourself, you don’t pay any labor costs. Having an auto mechanic change the belt can cost you between  $100 to $200.It is easy to find out all you need to know about serpentine belt replacement cost. Simply carry out an internet search with the entry “serpentine belt replacement near me”.

How To Tell When A Serpentine Belt Needs To Be Replaced YouTube

Frequently Asked Questions (FAQs)

What Does A Bad Serpentine Belt Sound Like?

Depending on the vehicle, a bad serpentine sound is similar to a screech, a whine, or a squeal. Whatever name you give the sound, it is loud and highly unpleasant and is one of the more obvious signs of a bad serpentine belt. Sometimes, this sound gets worse when you drive uphill or try to turn the steering wheel.

Can A Bad Serpentine Belt Cause Acceleration Problems?

Yes, it could. Bad serpentine belts cause loss of power. Especially in situations where slippage occurs and the alternator supplies power to the ECM. In such conditions, the alternator cannot provide the required electrical charge, and as a result, there is a drop in the voltage.

How Do I Know If My Drive Belt Needs To Be Replaced?

Another name for the serpentine belt is the drive belt. There are a lot of signs that indicate that the drive belt in your car is bad. The first step is to know these signs for what they are. The second step is to carry out regular vehicle inspections by yourself or with a mechanic’s help. Regular checks ensure that you can identify a bad drive belt as early as possible. Some of the signs you might notice are squealing, whining sounds, a damaged belt, and an overheating engine, among others. When you are quick to note these signs’ presence, especially bad serpentine belt tensioner symptoms, it becomes easier for you to detect when your drive belt needs to be changed.

What Happens If Serpentine Belt Breaks While Driving?

The vehicle shuts down after a while because the engine can’t operate with a broken serpentine belt. This is because the belt is responsible for a range of functions like steering wheel control. So when the serpentine belt breaks while driving, a range of things occur. For one, it becomes difficult to control the steering. The battery will die after a while since the alternator can no longer charge it. The water pump stops working too, so the engine starts to overheat after some time. At a point, the engine will pack up and will require being towed. So yes, a bad serpentine belt cause loss of power.

How Many Years Does A Serpentine Belt Last?

That depends on the material used in making the serpentine belt, how old your vehicle is, the way you drive, and the vehicle’s mileage. The brand of the vehicle also matters because the inspection intervals for different vehicles differ from vehicle to vehicle. By and large, the type of material used in making the serpentine belt matters a lot. The older serpentine belts that are made from Neoprene rubber do not last as long as the newer, improved belts made from  Ethylene Propylene Diene Monomer. All things being equal, the average serpentine belt can serve you for between 50,000-100,000 miles. With a well-maintained serpentine belt, you don’t have to worry about what causes a serpentine belt to break

Final Words

The serpentine belt of your vehicle is a thick strip of grooved rubber and metal that winds around several engine accessories that are powered by it. This explains why it is responsible for many engine and vehicle functions. That said, a bad serpentine belt in your vehicle is something that you do not want to have. Simply put, a broken serpentine belt can be dangerous for you and the health of your engine and vehicle.

Thankfully several symptoms are associated with a bad serpentine belt. So once you can identify bad serpentine belt symptoms, you can manage the situation before it deteriorates. Your best bet is to have a seasoned automotive mechanic inspect your serpentine belt, belt tensioner, and engine components regularly.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

Recent Posts