I changed the oil in my truck (99 f150) this weekend and noticed that the serpentine belt was looking pretty rough so I figured I would change it to be safe well went to a couple autoparts stores and no one had any in stock so I hit the pep boys near where I work and they had the belt great! however there were 2 sizes listed and the difference was 1 inch in the length. The shorter cost 23 bucks and the longer 36 and change. So I figured I would try the cheaper of the 2 and hope. of coarse the belt was too short so I ended up having to go back the next day and get the longer one. the install and removal of the old belt is a pain also I ended up using a breaker bar as the tensioner has a 1/2 inch drive slot in it and to get some length on it I broke out the good old steel pipe but routing the belt is a major PITA just a heads up for anyone else who is going to tackle this. Its not terribly hard just a little frustrating and you will need to go under the truck for sure and you will probably get dirty!

 

I changed the belt in my 04 FX4, it took me about 10 minutes once I figured out the pattern on it. Why did you need to go under the truck?

What kind of belt did you get?