im new here and my f250 light duty hit 110k miles and when i start it and rev it the belt sequels badly, i put on a new belt and from a search engine found this side and the picture below for the belt diagram when i noticed #5 idler pully is completely gone..no pulley or bolt. auto part stores sell them for around $23 but i have no bolt. no junk yards near me have a v8 truck to snag a bolt off of.

on a side note is there and good site's with part diagrams like the dealer has? the one below is ok but i like the ones that show part numbers for everthing including the bolts etc...i have an entire manual for my motorcycle and car downloaded on my computer but cant seem to find anything on my truck.

 

Your system probably doesnt use that pulley, mine doesnt. I would look at the tensioner and other idler pulley, number 1 and 2. Take the belt back off and spin them by hand to see if they are bad.

 

i took the belt off again, the water pump and idler pulley were quiet but the tensioner pulley was a bit loud....im guessing that's the problem but should i replace the entire thing or just the pulley? and for the missing one is it an option? i have the mount and looks like a peg all ready for a pulley to be there but i never recall ever having it.

 

so i replaced the tensioner, the stock one was loud when i spun it...however even still with the new tensioner and belt is squeels on acceleration, idle its fine and steady driving its ok so i think i need that other pulley for a little more tension to keep the belt from slipping??

 

You need to clean the pulleys and put a Gatorback belt on it.

 

Do you have a 4.6? I came across the problem when I did my 5.4 swap. My 4.6 didn't use it, and some 5.4s used it some didnt... I got a couple conflicting diagrams. I'm pretty sure when I got mine it came with a bolt

 

If its not on there, it probably didn't come with one. Out of the 4 2v 5.4's I have owned, none of them had it. Is it possible you got the wrong belt? Does the belt feel tight? As far as squeaks and screeches, sometimes they can be really loud when turning, but upon inspecting with the belt off only sounds like a light squeak or what not. I'm not even sure what that other idler was for, like I said, out of the 4 that I have owned, none of them had them.

 

the belt is tight and only screatches on acceleration. a couple times while driving... it definitely has the mounting location in the location of the pulley in the diagram.

 

They ALL have a mount on that side. Most factory engines came without the left idler.

Ford explains it like this - If your engine came without, -DON'T run one. If it came with, RUN one.

Simple. If you purchase a quality belt, you won't have a problem.