Symptoms Of A Bad Serpentine Belt And Replacement Cost

Do you suspect that your car's serpentine belt is bad? Here are all the symptoms as well as the estimated replacement cost.

Here are the main highlights:

  • A serpentine belt transfers power created by a car’s crankcase to vital engine components like the alternator and power-steering pump.
  • Symptoms of a bad serpentine belt range from the AC not working to dim or flickering headlights. The important part is to act before the issue escalates.
  • Expect to spend $69 to $180 or more on serpentine belt replacement, depending on your vehicle’s make and model.
  • Ultimately, checking your car’s serpentine belt with every oil change and following a routine service schedule should maximize its longevity.

I will start the guide off by explaining what a serpentine belt is. Let’s get started!

Table of ContentsShow

Serpentine Belt: Explained

serpentine belt

A serpentine belt, also known as an “accessory” or “drive” belt, is the most important belt in a car. This vital component connects and powers most of an engine’s supporting systems, like the alternator, AC compressor, power-steering pump, and others.

If there’s a problem with your vehicle’s serpentine belt, you’ll likely start seeing some signs.                  

What are the symptoms of a bad serpentine belt?

  1. AC stops working
  2. No power steering
  3. Squealing/flapping/whining sounds
  4. Visible belt wear
  5. Engine overheating
  6. Battery dash light appears
  7. Dim or flickering headlights

As for serpentine belt replacement costs, depending on hourly shop rates and job completion time, expect to spend between $69 and $180, if not more.

This article explores these symptoms and costs further. We’ll also answer some frequently asked questions about serpentine belts, including:

  • How long do serpentine belts last?
  • Is replacing a serpentine belt easy?
  • Are the serpentine belt and timing belt the same?
  • How long will a car run without a serpentine belt?

Let’s get started.

7 Symptoms Of A Bad Serpentine Belt

1. AC Stops Working

Car AC

Your car’s serpentine belt is connected and powered by the engine’s crankshaft. It winds around the engine, transferring power to vital components, which includes the AC compressor.

If something happens to the belt, like it breaks or is too loose, your vehicle’s AC system may stop cycling refrigerant.

2. No Power Steering

Another sign of a bad serpentine belt is your steering wheel requiring more effort to turn, especially at low speeds.

Similar to the AC compressor, your vehicle’s power-steering pump is also powered by the drive belt, so if it’s misaligned or snaps, you have an ongoing safety hazard.

3. Squealing/Flapping/Whining Sounds

noise while driving

Depending on what’s wrong with your car’s serpentine belt, it can make several sounds, including squealing, flapping, and whining noises.

Squealing and whining sounds usually indicate an issue with the belt’s tension, degraded springs, or extreme wear and tear. Flapping suggests the belt has broken.

4. Visible Belt Wear

If you inspect your car’s serpentine belt and see visible wear like cracks or fraying, you’ll likely soon notice other symptoms if you aren’t already.

A misaligned pulley or bad tensioner often causes premature belt wear, but it’s also possible the problem lies with one of the components it powers, like the water pump.

5. Engine Overheating

overheating engine

Speaking of the water pump, it, too, runs off the serpentine belt. Because of this, if your car’s accessory belt fails, your engine may overheat from not receiving enough coolant.

Moreover, other components powered by the serpentine belt will also generate excess heat, potentially causing some serious damage to your vehicle’s powertrain.

6. Battery Dash Light Appears

Your vehicle’s alternator is yet another vital part powered by the serpentine belt. Simply put, an alternator provides electrical power to your car once it’s started.

As you might imagine, a malfunctioning alternator can cause some serious problems. Thankfully, you should see a dashboard battery light suggesting a problem with your serpentine belt.

7. Dim Or Flickering Headlights

car headlights

Another symptom you might see is dim or flickering headlights caused by power supply issues from the car’s alternator.

Besides reducing your nighttime visibility, this issue can distract other drivers and potentially cause an accident.

Serpentine Belt Replacement Costs       

One nice thing about serpentine belt replacement is that parts should only cost about $50 at a reputable auto parts store.

As for how long it takes to replace a serpentine belt, shops usually estimate 15 minutes to one hour, depending on your vehicle’s model. With average shop rates ranging from $75 to $130 per hour, labor should cost between $19 and $130.

Add parts and labor together, and the total cost of replacing a serpentine belt ranges from $69 to $180, if not more.

Serpentine Belt: FAQ

How Long Do Serpentine Belts Last?

In most cases, a well-maintained vehicle shouldn’t have serpentine belt problems until after 50,000 to 100,000 miles. Checking your car’s serpentine belt for wear with every oil change is a great way to stay on top of problems before they happen.

Is Replacing A Serpentine Belt Easy?

Yes, mechanically savvy drivers will find replacing a serpentine belt on a modern car very easy. Models featuring automatic tensioners are especially simple, as there aren’t any nuts or bolts to worry about. Just rotate the tensioner, remove the worn belt, install the new one, and tighten it.

Are The Serpentine Belt And Timing Belt The Same?

No, both are not the same. The serpentine belt delivers power created by the crankshaft to various engine components. A timing belt (if equipped) also connects to the crankshaft but is paired with the camshaft to ensure the pistons ride and fall at the right time.

How Long Will A Car Run Without A Serpentine Belt?

Depending on the cause, expect your car to run up to 90 minutes before serpentine belt failure causes it to shut down. For example, if your motor overheats from a broken serpentine belt, it won’t receive enough coolant, potentially causing it to blow a head gasket.

Extend The Life Of Your Serpentine Belt By Following A Routine Service Schedule

As with all car components, your serpentine belt will last longer if you routinely maintain your vehicle.

Not sure how?

Check out our detailed service schedule guide.

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Joshua Barrett

Josh Barrett is a writer hailing from the great state of Alaska. While describing himself in the third person is not his forte, writing about any and all things automotive – is. After 13+ years hustling in the exciting world of car sales, he took off to travel the world with his dog Teemo.