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How to Loosen a Belt Tensioner

by Grace Mclain

The belt tensioner on all vehicles keeps the slack out of the belt and keeps the belt at the proper tension. The belt tensioner is spring-loaded with a pulley on one end that keeps the belt tight as the belt travels around each pulley. The belt travels around the alternator pulley, power steering pump pulley, water pump pulley, air conditioner pulley and the crankshaft pulley. Once that the belt tensioner wears out, it will need to be replaced.

Step 1

Park the vehicle on level ground and open the hood.

Step 2

Locate the belt tensioner on the front of the engine. The belt tensioner will have a spring-loaded arm on one end and a round pulley on the other end. The belt tensioner will also have a bolt head in the center of the pulley. This bolt head is used to relieve the tension from the belt. Some belt tensioners have a 3/8-inch square hole in the end of the spring-loaded arm that can also be used to relieve the tension from the belt.

Step 3

Rotate the pulley on the belt tensioner counterclockwise to relieve the tension of the belt with the proper sized socket and ratchet. Slide the belt off of the belt tensioner pulley. Let the belt hang down.

Step 4

Locate the mounting bolt in the center of the spring-loaded arm of the belt tensioner. Some vehicles come equipped with a belt tensioner that has a bolt head in the spring-loaded arm and some vehicles come equipped with an Allen head bolt that is in the center of the spring-loaded arm of the belt tensioner. Most tensioners also have one or two bracket bolts that hold the whole belt tensioner assembly to the engine block.

Step 5

Turn the bolt head in the center of the spring-loaded arm of the belt tensioner counterclockwise with a ratchet and socket to loosen the bolt. The tensioner will rotate freely before it comes to a stop. When the spring-loaded arm comes to a stop, continue to turn the bolt until the bolt loosens. Once the bolt loosens from the spring-loaded arm of the tensioner, release the belt tensioner until it comes to a stop. Finish unscrewing the bolt with your fingers.

Remove the other bracket bolts that hold the belt tensioner to the engine block. Use a ratchet and socket and turn the bracket bolts counterclockwise to loosen and remove the bolts from the belt tensioner bracket. Now, you can pull the belt tensioner straight off the engine block.


  • Make sure that the belt stays seated inside of all of the pulleys while loosening the belt tensioner. If the belt comes out of the other pulleys, you will have to use the belt routing diagram to reroute the belt around the pulleys. The diagram is located on top of the fan shroud on most all vehicles.


  • Always wear safety glasses when working inside of the engine compartment.

Items you will need

  • Flashlight
  • Ratchet
  • Socket set
  • Allen wrench

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