How To Replace The Air Conditioning Belt On A Cummins ISX Engine

A broken A/C belt will shut your air conditioner on a Cummins ISX engine down immediately as you travel over the open road. You need to replace the belt to get the A/C running again.The problem some drivers have is that they don't know exactly how the A/C belt snakes through the series of pulleys on the front of the engine block. If you are driving a truck with a Cummins ISX engine and you don't know how the A/C belt goes on the pulleys, here is how you can put a new belt on your truck so you can get back on the road.

Purchasing A/C Belt

You should be able to purchase a replacement A/C belt at a local auto store. You want to have an exact match. On the outside of the belt are a series of number and letters. If you still have the broken belt. either write down these numbers or take the belt with you to the auto store to make sure you purchase an exact match for the one that broke.

Placement of A/C Belt

The belt runs around a series of pulleys located behind the radiator and the main serpentine belt. You don't have to remove the radiator, but you do have to take the main belt off of its idler pulley so you can slip the A/C belt in behind it. The main belt idler pulley is in the center of the engine block and sticks about eight to ten inches. There is a slot for a quarter-inch-sized ratchet head to fit next to the main belt idler pulley. Place the ratchet in the slot and turn it clockwise to loosen the main belt so you can slide it off the main belt idler pulley. Do not take the main belt off of all the pulleys.

The A/C belt goes around three pulleys. The bottom pulley is for the water pump and is located in the middle of the front of the engine block. Drop the belt down behind the radiator and main belt and loop it around the bottom water pump pulley. Both the main and the A/C belts go over the water pump pulley. Make sure the A/C belt is behind the main belt on this pulley.

Slightly above the main belt idler pulley is the idler pulley for the A/C belt. The idler pulley is smaller than the main belt one and sits almost flush on the front of the engine block. Place the backside of the belt (the side with the numbers and letters on it) and stretch the inside of the belt around the A/C pulley at the top right of the engine block. The A/C pulley is the highest of all the pulleys on the engine block.

There is one pulley directly to the right of the A/C pulley and directly above the idler pulley for the A/C. You will need to adjust the idler pulley to create some slack in the A/C belt to get it around this pulley. Place the ratchet on the nut on the A/C idler pulley and turn it clockwise to create the slack you need. Put the inside of the A/C belt around the pulley and let the idler pulley fall back in position. The slack in the belt will tighten as the idler pulley moves back into position.

Place the main belt back over the idler pulley used for the main belt. Start the truck to make sure both the main and A/C belts are rotating normally and then close the hood. You are now ready to head back out onto the open road. For more information or help. contact truck repair companies, such as Color Country Diesel Inc.