By Peter Jones Founder, EditorPeter Jones Peter Jones, founder of Motor & Wheels, has a deep-rooted passion for cars. Growing up surrounded by automobiles, he authored a book on car parts aimed at new car owners. He has written hundreds of automotive articles and captured +500 car models as a car photographer. More about Peter Jones.Expertises: automotive industry, motor car, photography
A serpentine belt, also known as a drive belt, engine belt, multi-rib, or poly-v belt, is a crucial part of your car’s engine.
Let me explain exactly what it is and how it works.
Table of Contents
What Is A Serpentine Belt In A Car?
The serpentine belt transfers power from the engine’s crankshaft to the accessory pulleys. It’s designed to be thin and flat with multiple grooves or “ribs” on the inside, which match the rib pattern of the pulleys on the accessory units. This helps keep the belt in place and ensures smooth functioning.
This single, continuous belt is used to drive multiple peripheral devices in an automotive engine, such as:
- Alternator
- Power steering pump
- Water pump
- Air conditioning compressor
- Air pump
What Does A Serpentine Belt Look Like?
The serpentine belt has a snake-like appearance – which is where it gets its name. It is constructed from rubber and reinforced with fiberglass or Kevlar cords.
You can usually spot this belt in the front of the engine block.
Your serpentine belt will usually have ribs or grooves along its inner surface. These help the belt grip the various pulleys it’s wrapped around and prevent it from slipping. It’s not too wide, but its length varies depending on your car’s particular setup.
The color of a serpentine belt can range anywhere from black to dark blue or even grey. Over time, it might begin to look dirty or covered in grime due to the dust and debris it encounters while your engine runs.
Do All Cars Have Serpentine Belts?
Not all cars actually have a serpentine belt. Before timing and serpentine belts became standard, many older cars used timing chains and V-belts.
New gas or diesel-driven cars, however, have serpentine belts.
You also don’t find serpentine belts in electric cars.
Where Is The Serpentine Belt Located?
If you pop your hood and peek at the engine, you can see the serpentine belt spinning around several parts and pulleys. These pulleys are connected to various components like the alternator, power steering pump, water pump, air conditioning compressor, and air pump.
In case you’re still having trouble spotting the serpentine belt, consult your owner’s manual for the exact location and a diagram of your engine’s layout.
Now, you might encounter a situation where some components or engine covers obstruct the serpentine belt, making it slightly trickier to get to. Though not impossible, gaining access to the belt might require the removal of a few parts.
Remember, you can also refer to the serpentine belt routing diagram in your owner’s manual or under the hood for guidance on locating and working with the serpentine belt.
How Long Do Serpentine Belts Last?
Serpentine belts on older cars normally last up to 50,000 miles. Newer serpentine belts made from EPDM (ethylene propylene diene monomer) can keep on going for up to 100,000 miles.
How Much Do Serpentine Belts Cost?
New serpentine belts cost from $25 to $75. The price for a used belt may range between $10 and $30.
To give you a clearer picture, here’s a handy table with the approximate costs.
| Belt Type | Price Range |
|---|---|
| New | $25 – $75 |
| Scrap Yard | $10 – $30 |
However, it might not be worth it as used serpentine belts may already be worn.
You might also find them online. Besides serpentine belts, you can search for “engine belts” or “drive belts“. It’s the same thing!
How Much Does It Cost To Replace A Serpentine Belt?
The labor cost for replacing a serpentine belt can range from $80 to $250. The actual cost depends on how accessible the belt is on your specific car model and of course, the hourly fee of the mechanic is a factor.
What Happens When A Serpentine Belt Breaks?
When your serpentine belt breaks, you’ll likely notice some immediate symptoms. You may hear a squealing noise coming from the front of your vehicle, indicating slippage or misalignment of the belt.
Your engine might also start to run less smoothly.
Can you continue driving with a faulty serpentine belt?
As for driving without a serpentine belt, it’s not recommended – even for short distances. Your vehicle’s engine relies on this belt to operate smoothly, and without it, you might face costly and potentially dangerous consequences.
The belt is responsible for transferring power to multiple components in your car’s engine, so when it breaks or malfunctions, those components won’t receive the power they need to function properly.
For example, you might experience problems with:
- your power steering,
- air conditioning,
- and alternator.
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Can You Replace A Serpentine Belt Yourself?
Sure, you can replace a serpentine belt yourself.
What you’ll need:
- Correct replacement serpentine belt for your car
- Basic hand tools (sockets and wrenches)
- Tensioner tool or long-handled wrench
Step 1: Locate the serpentine belt. Look around under the hood, and you should see the serpentine belt snaking around various pulleys.
Step 2: Study the belt routing diagram. Most vehicles have a diagram under the hood or in the owner’s manual. This will help you reinstall the new belt correctly. If you can’t find a diagram, take a picture of the current belt routing before you remove it.
Step 3: Release tension and remove the old belt. Using a tensioner tool or a wrench, apply pressure to the tensioner pulley to release tension on the serpentine belt.
Slide the belt off the pulleys and unwind it.
Step 4: Compare the old and new belts.
It’s always a good idea to compare the old belt to the new one, making sure they are the same size and type.
Step 5: Install the new belt. Following the belt routing diagram or your picture, start threading the new belt around the pulleys. Keep in mind, you’ll need to hold the tensioner slack with one hand while you finish routing the belt.
Step 6: Check the alignment. Ensure the belt is properly seated on all pulleys and within grooves. Misaligned belts can cause premature wear or damage to the belt and pulleys.
That’s it! You’ve successfully replaced your serpentine belt.
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