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F150 Serpentine Belt Replacement

How to Replace the Serpentine Belt on a 4.6L/5.4L V-8





Belt squeaking or squealing upon start up is the first sign that the serpentine belt needs to be replaced. Eventually, the noise will stop going away after start up and will occur continuously. Replacing the belt is fairly straight foward, as all that's needed is a 1/2 inch breaker bar or belt removal tool. The procedure is easier with two people, as the belt tensioner is made of soft aluminum and easy to strip if you don't maintain a solid grip on the 1/2 inch drive square socket. Should you strip the nut, a new belt tensioner is 3 bolts to install and your local auto parts store should carry one for under 50 dollars. To reduce the chances of stripping the tensioner socket, operate the breaker bar with one hand while pushing inward on the head of the bar with your other. Meanwhile, have a second pair of hands slip the belt off of the alternator.


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• Make sure you have the correct belt length and rib count. These vary depending on model year and engine.
• Locate the belt tensioner (picture below). On our test vehicle, the belt tensioner assembly is located passenger side on the front of the engine (just below the alternator).
• Insert your 1/2 inch drive breaker bar or belt tensioner tool into the front of the tensioner. The tensioner is made of very soft cast aluminum, so ensure your tool is fully inserted before continuing (picture below shows detailed location).

• Push your tool clockwise (towards driver side) to release tension on the belt. While maintaining pressure on the tensioner, pull the belt off the top pulley (in our case, the alternator). Release the tensioner and completely remove the old belt.
• Study the diagram found on the fan shroud or in your owner's manual and begin installing the new belt to those specifications. It is vital that the belt is installed per this diagram.
• You should have the belt installed with the exception of 1 pulley. Once again use your 1/2 inch drive tool to release tension on the belt. This should allow you ample room to install the belt over the last pulley.

• With the belt completely installed, release the tensioner and double check your work.