How To Replace a Serpentine Belt? – In Six Easy Steps

How To Replace a Serpentine Belt

The serpentine belt in most modern vehicles transmits power from the crank pulley to the various engine-mounted accessories. A worn or damaged serpentine belt cannot transfer the power sufficiently, so your alternator, power steering, and air conditioning system will no longer work. You can replace a serpentine belt using only common hand tools.

To replace a serpentine belt, you only need a few things: a new belt, a belt tensioning tool, and maybe a socket wrench. These things should be easy to find at an auto parts store. Gloves and eye protection never hurt either.

Every car engine is different, even engines from the same car manufacturer. This means that the serpentine belt snake around the pulleys in a different order as well. Newer cars may have a plastic cover over the engine that needs to be removed so you can see what’s going on with the belt. If your engine is cold, open the hood and get your bearings.

How To Replace a Serpentine Belt?

If you have the tools and knowledge, here’s what you need to do to replace a bad serpentine belt:

  • Step 1: Note the placement of the belt
  • Step 2: Examine the tensioner
  • Step 3: Loosen and unthread the belt
  • Step 4: Check for damage
  • Step 5: Examine each pulley
  • Step 6: Install the new belt

Here are the details of the serpentine belt replacement procedure:

Step 1: Note the Placement of The Belt

Depending on the engine in your vehicle, the serpentine belt may be located at the front of the engine compartment or on one side. Engine covers may get in the way, so be prepared to remove them if necessary.

Once you locate the serpentine belt, visually inspect it for signs of damage. If the belt is frayed, coming loose, or shows marks that indicate it has rubbed against something, it will need to be replaced.

To preserve the belt’s position, use your phone to take a picture of the existing belt from different angles, or sketch how it winds through the engine. If the belt has already out of place, find the driver’s manual or the label under the hood where you will find a sketch of the route.


Step 2: Examine the tensioner

Depending on the application, your serpentine belt will be tensioned with either a moving bracket or an automatic tensioner. This pulley uses an internal spring to apply consistent pressure to the belt at all times.

A “good” tensioner arm should only vibrate slightly with arm movement of about 1/32 inch or less. And the belt should run smoothly with no visible vibration.

If your vehicle does not have a tensioner pulley, it is likely the alternator bracket that controls the tension of the belt.

Step 3: Loosen and Unthread the Belt

Before removing the belt, you must loosen the tensioner that automatically keeps the belt taut while riding. Tensioners typically have one of two ways of releasing tension.

Automatic tensioners either have a hole that accepts a half-inch ratchet or a bolt that you can apply pressure to with a socket wrench. Insert the wrench or socket over the bolt on the tensioner and rotate away from the belt to relieve the tension.

Depending on the position of the tensioner, you may need to turn the tensioner clockwise or counterclockwise. Be sure to use the correct size socket to avoid stripping the bolt head on the tensioner.

Step 4: Check for Belt Damage

Once removed, inspect the belt for signs of damage. Many belts wear out over time, but some wear out due to misalignment or other issues. If your car’s drive belt has multiple cracks on adjacent belt ribs within one inch or more than four cracks per inch on a single rib, you need to replace the belt. A misalignment will not resolve itself when you replace the belt, so determine if this is a problem.

How To Replace a Serpentine Belt

Step 5: Examine each pulley

Rotate the tensioner and slide the drive belt off the pulley/roller. Then spin the pulley/roller and feel for resistance, binding, and roughness. Then spin it and listen for a rumble. If it doesn’t spin smoothly or has a rough surface, replaces it.

Use a straightedge to make sure the pulleys are aligned properly, then clean any old dirt and grime from the pulleys. This is also a good time to check for oil leaks. Oil can increase the wear of serpentine belts.

Step 6: Install the New Belt

Now you will be glad to have diagrams and photos. Put the belt back on all the pulleys in the correct order for your vehicle.

Remember that any grooved pulley is designed to be driven by the grooves in the serpentine belt. For example, the idler pulley has no grooves because it rests on the back of the belt. But the power steering pump pulley has grooves. You literally have to get your groove on here for the power of the crankshaft to spin these accessories.

Keep the tensioner loose while you thread the last pulley. Once everything is in place and the grooves are in place, use your belt tensioner or socket wrench to tighten the tensioner pulley.

It’s time to try. Dear readers, start your engines! Let it run for a minute or two to make sure it’s seated properly and everything is working as it should.

What Does A Worn Serpentine Belt Look Like?

A new serpentine strap has a soft, felt-like finish on the ribbed side. As the belt wears, the belt rubber hardens and cracks. A worn belt stretches and loses tension. This will cause the belt to slip from time to time.

You can hear it as a squeaking or chirping noise under the hood in the morning when starting the engine or in wet weather. The belt can also appear glazed. If there are no other problems and the belt tensioner is fine, a new serpentine belt should fix this problem.

Can I replace a serpentine belt myself?

Serpentine belt replacement is easy because today’s automatic drive belt tensioners eliminate the need to loosen bolts or pry components into position for tensioning. Just rotate the tensioner, remove the old belt and install a new one.

How do you change a serpentine belt at home?

How much should it cost for a serpentine belt replacement?

The cost of the serpentine belt itself could be around $50 and the cost of labor could be around $150. As a result, a serpentine belt cost for replacement could range from $70 to $200 depending on your exact model and where you get it replaced.

How long does it take to replace a serpentine belt?

Under ideal circumstances, your car’s serpentine belt should last 60,000–100,000 miles. It’s important to replace this belt as part of your vehicle’s scheduled maintenance (even if it looks okay) to avoid it breaking while you’re on the road.


Leave a Comment

On Key

Related Posts

What Others Are Asking

Here’s How Your Car Engine Works

A car engine consists of a fixed cylinder and a moving piston. The expanding combustion gases push the piston, which in turn rotates the crankshaft. Ultimately, through a system of gears in the powertrain, this motion drives the vehicle’s wheels.

What Is Serpentine Belt in Car?

A serpentine belt is an important part of your vehicle’s engine block, but do you know what a serpentine belt really is? And what does