How to Tension a V-Belt

by Kevin Mclain

A v-belt is the main component that turns certain engine accessory pulleys. A v-belt operates different engine accessories such as the alternator, power steering pump, water pump and the air conditioner compressor. The belt is driven around each accessory pulley by either the crankshaft pulley or another pulley that the v-belt operates. Some vehicles come equipped with as many as three v-belts. Excessive turning around the accessory pulleys can cause the v-belts to develop cracks and tears. Replace the belt before the cracks worsen and the belt breaks. If the v-belt breaks, the engine accessories will stop working immediately.

Park the vehicle on a flat surface and wait a couple of hours for the engine to cool off. Open the hood and lock it in place.

Inspect the area of the v-belt in need of tensioning and locate the adjustable belt tensioner. Most vehicles that come with a v-belt also comes with an adjustable belt tensioner. If not, the engine accessory that the belt operates must be loosened from the engine to tension the belt. General locations for a v-belt tensioner are below the alternator, attached to the power steering pump or below the air conditioner compressor. The tensioner will be a bracket with an adjustable bolt sticking out of the bracket.

Loosen the front locking bolt that secures the adjustment bracket to the engine accessory with a ratchet and a socket. Loosen the mounting bolt that secures the engine accessory to the engine with the ratchet and socket.

Turn the adjustment bolt at the end of the bracket clockwise to tighten the belt. Once the belt is tight, tighten the lock bolt on the front of the bracket back down tight with the ratchet and socket.

Check the tension of the belt by pushing inward on the belt with your hands. The belt should have no more than a 1/2 inch of slack to be properly tensioned. Adjust the belt as needed from the adjustment bolt until the slack in the belt is no more than a 1/2 inch. Tighten the mounting bolt to the engine accessory with the ratchet and socket. If the engine accessory that the belt operates has no adjustment bracket, the mounting bolts to the accessory must be loosened.

Loosen the mounting bolts to the engine accessory with a ratchet and a socket. Slide a pry bar between the engine accessory and the engine. Pry against the accessory until the belt is tight. Once the belt is tight, hold the pry bar with one hand and tighten one of the accessory mounting bolts with the other hand.

Check the tension of the belt by pushing inward on the belt with your hand. The belt should have no more than a 1/2 inch of slack. Adjust the belt tension as needed with the pry bar until there is no more than a 1/2 inch of slack in the belt. Tighten the remaining accessory bolts with the ratchet and socket.

Crank the engine and let it run for about one minute. Turn the engine off and recheck the tension on the belt with your hand. Adjust the tension of the v-belt if necessary.

Tips

  • check A v-belt tension checking tool can also be used to check the tension of the belt. The tensioner tool can be found at most auto parts stores.
  • check The only two places that a v-belt can be tensioned from are the adjustment bracket that is attached to the engine accessory or by prying against the accessory with a pry bar.

Warning

  • close Do not over-tighten the v-belt. If so, the belt could break while the engine is running. This is the reason for leaving the 1/2 inch of slack in the belt.

Items you will need

References

About the Author

Kevin Mclain has more than 20 years of automotive, home improvement and landscaping experience. He has been writing for various online publications since 2002. Mclain has U.S. Army certification in automotive maintenance and repair, among more than 15 additional certifications related to the automotive field.

Photo Credits

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