- Written ByJohn Goreham
- 7/11/2024
Edited ByJulie Bausch Lent
Shop Serpentine Belts For Your Car
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One indispensable part of your engine that you will likely replace a few times during your vehicle’s lifespan is its serpentine belt, a.k.a. accessory drive belt. This is a job with a very reasonable cost. Your budget for a serpentine belt replacement should be around $200.
What is a Serpentine Belt?
The serpentine belt in your engine bay is responsible for making your AC compressor and alternator work. On older cars, the belt may also run your car’s power steering pump and, in some cases, the water pump. Without this belt working and working properly, your car will not run. There was a time when the cooling fan in your car’s engine bay was run off a belt, but most modern cars today use electric fans, so the name “fan belt” is no longer used much.
The belt itself is a composite of rubber, specialty textiles, and fiberglass. It’s about a half-inch thick and many feet long. It is a circle when stretched out and not wound around the engine bay’s components. The inside of the belt is often ribbed, but not always.
Is a Serpentine Belt the Same as a Timing Belt?
No, a serpentine belt is not the same as a timing belt. Serpentine belts operate outside the engine. Vehicles that use timing belts have them encased or enclosed. Replacing a timing belt is a more complicated and more expensive job. The timing belt’s job is entirely different from what a serpentine belt does.
How Does a Serpentine Belt Work?
Your engine’s crankshaft powers and spins the serpentine belt. The belt winds its way around some very important components. The belt uses friction to grip the pulleys attached to the components it powers. The belt rotates constantly. Each component uses a clutch mechanism to take power only when needed from the rotating belt.
Why Do Serpentine Belts Fail?
Serpentine belts operate in a hot area and are often splashed with water and salt from roadways. Although the belts are made robustly, they can and do wear out. They typically fail over time, and stretching and cracking are often detectable by your mechanic, who may recommend that you proactively replace the belt.
Another way the belts fail is if they are rotating but a pulley is offering resistance or not turning. This can happen if the bearing inside of a component fails and seizes. If your mechanic replaces your alternator or AC compressor, she may also replace the serpentine belt and a part called a tensioner.
Tensioners are in the loop the serpentine belt follows. These require some adjustment. If the tensioner fails, is misaligned, or is not properly adjusted, it can cause damage to the serpentine belt.
Finally, if any of the fluids your vehicle uses leak or spray when they should not and contaminate the belt, it may suffer damage and require replacing.
How Do I Know If My Timing Belt Is Damaged?
These are the symptoms of a failing serpentine belt:
- Check Engine Light Illuminates
- Screeching, squeaking, or chirping noises from the front of the car
- AC has stopped working
- Your battery warning light illuminates (indicating alternator trouble)
- Your car’s power steering is not working properly or is intermittent
- The engine is overheating (warning light, temp gauge shows overheating or vapor is visible)
As you can see, the symptoms of a problematic serpentine belt are all related to the accessories that it powers. The exception is a screeching sound, which is indicative of the belt slipping.
Do I Really Need To Replace My Serpentine Belt?
Yes, you do need a properly working serpentine belt, so replace it if you discover it is not right. A car can run for a while without one, but you may risk overheating or killing your battery. Get it done proactively, if possible, before trouble starts.
How is a Serpentine Belt Replaced
The belt is replaced by moving the tensioner and removing the old belt if it is still on. Next, the new belt is installed, and the tensioner is properly aligned and adjusted. A skilled mechanic can do this job in about 15 minutes.
Who Can Replace My Serpentine Belt?
Any skilled mechanic can replace your serpentine belt. An auto repair chain can handle this job, and, of course, your dealer. Of the options available, expect to pay the most at the dealership.
Can I Replace My Own Serpentine Belt?
If you are handy with tools, have above-average levels of patience and hand-eye coordination, and have a positive attitude, replacing a serpentine belt is within your capabilities. This job is easier if the belt is still on the car. You may need to bend and twist to make this work, and it is very wise to take before images so you can see how the belt was on before you begin. A YouTube video tutorial would be a great idea.
How Much Does It Cost To Have a Serpentine Belt Replaced?
A serpentine belt is an affordable item, usually costing between $35 and $150. Your mechanic may charge you a half-hour or hour of labor to do the work. Budget around $200 for this job, and be happily surprised if it costs you less. If you have a dealer do the work, add about 30% to the cost, and if you own a fancy specialty vehicle, the sky's the limit on cost.
Read more on the topic of Owning a Car here.
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