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How To Diagnose A Failing Serpentine Belt

When your serpentine belt begins to fail, many parts will stop working as well as they should. It's because the serpentine belt powers many different accessories, including:

When these parts don't work well, a lot of problems will crop up. For example, your engine may start to overheat. That's why it's important to diagnose and replace a failing serpentine belt before it actually fails. We'll show you how to do that in this post.

Signs Of A Failing Serpentine Belt

Failed vw battery

The first step in diagnosing a failing serpentine belt is to look for signs of trouble. Here are some common symptoms:

  • Engine overheating
  • Squealing or chirping noise from the engine compartment
  • Reduced power steering assist
  • A/C system blowing hot/warm air
  • Dead car battery

It's common for a failing serpentine belt to cause two or more of these symptoms at the same time. If you notice any of these symptoms, it's time to inspect the serpentine belt.

How To Diagnose A Failing Serpentine Belt

Worn serpentine belt

Now that you know what symptoms to look for, let's take a look at how to diagnose a failing serpentine belt. You don't need any specialized knowledge or fancy tools to recognize a bad serpentine belt. All you need to do is check the belt's tension and inspect it for any signs of damage.

Before you can inspect the serpentine belt, you need a clear view of the serpentine belt path. That means you should be able to see the belt routing, idler pulley, tensioner, and all of the accessory pulleys. The best way to access it depends on your engine. Sometimes it's as simple as removing the engine cover. Other times you might just need a good flashlight. If you're not sure how to access the belt, consult your vehicle's service manual.

Once you have a clear view of the belt, it's time to inspect it for damage.

Checking The Belt Tension

The belt should have just enough tension to keep it in place. If there's too much tension, it can wear out prematurely. If there's too little tension, the belt can slip, and not provide full power to the pulleys.

You can check the belt tension by twisting the belt with your hand and feeling for any play. Be sure to twist the middle part of the belt in between two pulleys. You should not be able to twist the belt more than 1/4 turn. If you tug on the belt, you shouldn't be able to pull it more than 1/2"

If there's too much or too little tension, there may be damage on the belt.

Checking The Serpentine Belt For Visible Signs Of Damage

In addition to checking the belt tension, you should also look for any visible signs of damage. The most common types of damage are cracking and fraying. You can also look for chunks missing from the belt, or deep gouges.

If you see any damage on the belt, it's time to replace it.

Need A Replacement Serpentine Belt?

If you need a replacement serpentine belt, we have what you need. We're an authorized retailer of genuine OEM Volkswagen parts. Our catalog of belts and hoses has OEM serpentine belts for a variety of VW models. Look up your VW model to find the right serpentine belt. Please contact us if you need help with this.