Replacing The Serpentine Belt

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My mechanic dropped a bomb on me!

That high-pitched squealing noise coming from my car’s engine bay was the failing serpentine belt. 

And I didn’t even know. 

Most car owners ignore the signs of a bad serpentine belt as if they are normal. But let me tell you, a failing serpentine belt will break your car down and destroy the engine.

Therefore, in this article, I’ll highlight five signs of a bad serpentine belt and easy ways to replace it.

Stick around!

Signs of a Bad Serpentine Belt

As astounding as it sounds, serpentine belts do not show obvious symptoms of losing tension.

However, they show some common symptoms that might link to their failure, including squeaking sound, dry rotting appearance, or low tread in the bottom. 

Whatever the case may be, a failing serpentine belt means your vehicle won’t drive at full efficiency without its forced induction.

Also, the accessories, including AC, alternator, power steering, and water pump, associated with the serpentine belt stop working.

Here are a few signs of a failing serpentine belt.

Loud Squealing Sound

A loud, unpleasant squealing sound is one of the most common symptoms of a bad serpentine belt.

Serpentine belts are made over rubber using small teeth for the strong gripping of the wheels they operate.

As soon as the rubber wears down, the belt starts to slip or doesn’t move at all. It results in a loud squealing sound from your vehicle’s engine bay.

However, I recommend having the strange noises inspected by a professional mechanic before jumping to conclusions.

Worn-out Engine Belts

If your engine belt occasionally snaps, leaving you stranded, it’s best to replace your belt.

You may also notice damaged ribs, cracks, missing pieces, separating ribs, abrasions, causing your belt to slip.

Even though quick fixes like lubricants are available, there’s no safe substitute for qualified maintenance.

Quick tip to check for wear and tear:

  1. Twist the belt and examine the inside.
  2.  If cracks are present on the surface, your belt needs to be replaced.

Engine Overheating

One of the first signs of a failing serpentine belt is the excessive overheating of your car engine.

Like I mentioned before, the water pump is associated with the serpentine belt.

The water pump circulates the coolant through the engine and radiator, and without this, your engine will overheat regularly.

Therefore, if your engine is not running smoothly, it’s a strong indication that your serpentine belt is slipping and needs replacing.

Malfunctioning Accessories

Several functions on your car, including air conditioner, power steering, battery, and alternator, depend on the serpentine belt.

The alternator is responsible for keeping your battery charged and running other electrical accessories. Without an alternator, your electronic accessories get an inconsistent voltage that results in over-or under-performance of the equipment.

In extreme cases, the engine might rapidly overheat, leading to severe engine damage.

Snapped Serpentine Belt

As a responsible car owner, you should never allow the problem to get to this stage.

A snapped or fallen-off serpentine belt is the last indication your vehicle would give for due replacement. It all begins with cracked or frayed edges, followed by loud squeaky sounds, finally ending with a snapped belt.

If you suspect that your serpentine belt has fallen off the pulleys, examine the hanging belt and bits of it under the car or around the pulleys under the hood.

In most cars, the belt gets tangled with the timing belt, causing tremendous damage to the engine.

Therefore, always do the regular maintenance of your vehicle and use quality parts to avoid such mishaps.

How to Replace a Serpentine Belt

Most serpentine belts last for around 150,000 miles, depending on their condition and upkeep.

However, if you hear a squealing sound or a loud racket that stops after a few seconds, know that you need to change your serpentine belt.

Replacing your serpentine belt is a clear-cut task, especially if you follow the correct step-by-step guide.

Preparing your Vehicle

First things first, you need to begin with inspecting the serpentine belt. It’s the best way to determine if you need to replace the belt.

Even if your serpentine belt is intact, look out for minor wear and tear. The failing belt has damaged ribs, inner cords, and minor effects of fraying.

Once confirmed, get your car ready.

  1. Park your car on a flat surface and turn off the engine with the parking brake “on”.
  2. Wear gloves, protective gear, and clothing.

Step-by-step guide

Step 1: Popping the hood of your vehicle

You need to pop your hood to access the serpentine belt. The hood release can be found inside your vehicle. Just press, push or pull it until you hear your hood pop open.

Besides the hood, release the safety latch located below the steering wheel or at the vehicle’s front.

Step 2: Disconnecting the battery

Rule number one in DIYing any automotive project is always to work safely.

Therefore, it’s imperative to disconnect the battery using an appropriate size wrench to lose the nut, disconnecting the battery’s negative terminal.

There’s no need to disconnect the positive terminal.

Step 3: Locating the serpentine belt

Stand in front of your car and take a look at the engine compartment, you will see that the serpentine belt is located on the left side.

Remove the air cleaner box and move the hose attached to it to access the belt properly.

Next, separate the air cleaner and pull up the box directly. It should slide out effortlessly. Set it aside.

Now taking the hose side and bending it towards your transmission dipstick, secure it using a string or a bungee.

In case you don’t find a serpentine belt, refer to the user manual for your vehicle.

Step 4: Finding the serpentine belt routing diagram


If not, make sure to draw a diagram or take a picture to install the belt correctly.

Step 5: Finding the tensioner


Using a ⅜” ratchet, find the tensioner. The square slot will allow you to put your ⅜” ratchet and turn it, relieving the tension on the belt. Then, take the old belt out.

However, the ratchet should have a very long handle to assist in turning the tensioner effectively.

Step 6: Replacing the serpentine belt

Compare the new belt with the existing one to ensure the width and number of ribs. You should buy the best serpentine belt and make sure to check the compatibility carefully before buying a new one.

The old belt might appear slightly longer than the new one due to stretching.

Step 6: Routing the belt

Following the route diagram, run the new belt through the pulleys.

Lastly, apply some pressure on the auto tensioner and put the belt over it.

Step 7: Double checking everything

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Make sure the belt is aligned precisely and running smoothly.

Final Thoughts

The squealing sound, loss of power steering, or engine overheating might not be alarming at first.

However, if it happens repeatedly, call your mechanic immediately to diagnose the problem before it is too late.