The idler pulley on a Dodge engine is the smallest pulley on the engine. Its job is to guide the drivebelt around the front of the engine and keep it connected to the rest of the pulleys. There will be a large nut in the center of the pulley that secures it to the engine. You will need to know which direction the idler pulley turns because the nut must be turned in the opposite direction.
Open the hood and connect the wrench to the pulley's nut with the metal brace mounted to the top of it: this is the tensioner pulley. Turn the nut until the drivebelt loosens. Pull the belt off of the engine pulleys.
Connect a socket to the impact wrench. Connect the impact wrench to the air compressor. Start the air compressor and allow it to charge for 10 minutes.
Place the socket over the nut in the center of the idler pulley and hold the pulley with your other hand. Turn the nut in the opposite direction that the pulley turns with the impact wrench. Pull hard on the pulley and wiggle it until the pulley comes off of the engine.
Place the new idler pulley onto the engine. Push hard on the pulley until it is all the way onto the engine. Place the nut on the bolt in the center of the pulley. Place the socket over the nut and use the impact wrench to tighten the nut.
Replace the drivebelt onto the engine pulleys according to the diagram on the engine. Tighten the belt with the wrench to fasten the nut in the center of the tensioner pulley.
