How to Change the Tensioner Pulley on Vehicles

by Contributing Writer; Updated June 12, 2017

The Vehicles automatic serpentine belt tensioner assembly consists of a tensioner hub, tensioner arm and tensioner pulley. The pulley rides on the serpentine belt, applying the tension provided by the spring-loaded tensioner arm. Inside the pulley is a bearing ring that allows the pulley to spin freely as the belt moves across the pulley's surface. The main cause of pulley failure is bearing damage, which can either lock the pulley in place or fail to keep it aligned with the serpentine belt. The tensioner pulley itself is not serviceable apart from the tensioner assembly, so you'll need to replace the entire assembly to change the tensioner pulley.

Under The Hood:

 How to Change the Tensioner Pulley on a Nissan Xterra

Pull the emergency brake and chock the wheels of the car. This is an important safety step, as it prevents the car from rolling or moving while you are working on it.

Open the hood and determine the location of your serpentine belt and tensioner. This will be on the front of your engine block. If your car does not have a routing diagram for the serpentine belt on the underside of the hood, draw a diagram on a spare sheet of paper.

Place the head of the 3/8-inch drive ratchet in the hole of the tensioner pulley, and apply pressure counterclockwise to remove pressure from the serpentine belt, then remove the belt from around the tensioner pulley. There is no need to remove the belt from all of the pulleys that it services. Move the belt far enough from the tensioner so that you have ample room to work.

Determine what socket size you need to remove the tensioner and tensioner pulley. The bolt head that you need to loosen is the one located on the front of the tensioner, as opposed to the one on the tensioner pulley. Using the socket and ratchet, loosen and remove the bolt.

Remove the tensioner assembly from the engine and place it to the side.

Install the new assembly and replace and tighten the bolt until it is secure. Make sure that the bolt is tightened well, as engine vibration can cause a loose bolt to work itself loose.

Replace the serpentine belt around the tensioner pulley and refer to the routing diagram to ensure that it remains in its proper position around the other pulleys. Insert the ratchet head into the hole on the front of the pulley and apply pressure in a counterclockwise direction to reapply pressure to the serpentine belt.

Items you will need

  • 3/8-inch drive ratchet

  • Socket set

  • Tensioner pulley replacement parts

 How to Change the Tensioner Pulley on a Cavalier

Park the car on a flat, paved surface and set the parking brake.

Open the hood to access the engine compartment. Locate the tensioner pulley between the alternator and the power steering pump. Place a bare socket wrench onto the hex-shaped hole at the end of the tensioner. Pull the socket wrench back to loosen the belt. Pull the belt off the pulley.

Unscrew the bolt holding the tensioner pulley in place with a socket wrench. Pull the tensioner away from the engine.

Replace the tensioner pulley with a new one. Push the bolt in and tighten it with the socket wrench.

Push the tensioner pulley down so the belt can slide over the pulley. Slowly release the socket wrench to tighten the belt.

Start the car and allow it to idle. Observe the belt to make sure it is not sagging along the belt path. If the belt is sagging, then the new tensioner pulley may not be any good.

Turn the car off and close the hood.

Items you will need

  • Socket wrench

  • Socket set

 How to Change a Tensioner Pulley on a Nissan Patrol

Open the Nissan Patrol's hood and hold it open with the prop rod. Note the position and location of the automatic belt tensioner on the face of the engine as illustrated on the serpentine belt diagram, which you'll find on the fan shroud.

Rotate the Patrol's automatic tensioner off the serpentine belt using the serpentine belt tool. Pull the serpentine belt out of the tensioner pulley path with your other hand while slowly rotating the tensioner back into position.

Unbolt the automatic belt tensioner from the Patrol's front engine cover using a socket set. Lift the old tensioner assembly out of the Patrol's engine well by hand.

Place the new automatic tensioner on the front engine cover by hand. Thread the bolts through the automatic tensioner and into the front engine cover by hand. Tighten the automatic tensioner bolts with a socket set.

Reinstall the Patrol's serpentine belt in the reverse sequence of how you removed it. Close the Patrol's hood.

Items you will need

  • Serpentine belt tool

  • Socket set

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