Replacing a drive belt in my1989 Ford F-250 351W 5.8L requires a 94 inch belt. I took the old belt off. Checked belt tensioner and all pulleys, all spin freely and none wobble. Ok time to put new belt on, but wait it doesn't fit?! This time I double checked my tensioner, and pulleys, all checked good and also checked the brackets, good as well. Checked routing diagram to make sure I was doing it right and I was. Tried to put belt on again, didn't work. Yes I am pulling tensioner all the way.

The only way I could get the new 94 inch belt to fit was by swapping the way the belt goes around the crankshaft and fan. Which is wrong the engine isn't getting cooled. Any solutions?

 

Is the New belt the same size as the old one?

 

Yes both are 94.470" I was thinking about getting a 95.236" belt. I'm sure the extra .766" would be enough without making it too loose. (The Guy who owned it before me probably messed a bunch of crap up. I've been fixing his mistakes left and right)

Also I did put it on backwards on purpose knowing that the fan would start pushing air and not pulling it and drove around a little. With that said it meant the crank pulley was also spinning the wrong way. Seeing as it's a non interference engine I didn't see a problem with trying it. What (if any) damage could I have done from a 10min drive?

 

If the old belt and new belt are rated exactly the same and physically measure close to the same size you issue is with belt alignment.

Many times I have swore I had the belt on each pulley correct but could not get it under the tensioner pulley. Turns out I was one rib off front to back on a pulley or two. Problem solved.

 

I got the belt on thanks. I had the right size for some reason when I was laying under the truck I didn't mentally turn the image around in my head and was actually putting it on backwards. Feel kinda stupid now LOL. I'm going to start a thread about an exhaust system change out and post lots of pictures. Thanks guys