When i first start my truck with a cold engine the belt slips/squeals for 3-4 seconds.With a warm engine it doesn't happen.Replaced the belt.No help.The back (smooth side) of the belt looks shiny/glazed as if it has been slipping.Is this normal on startup? or possibly a weak tensioner?

 

try a tensioner. but to me that sounds like your harmonic balancer starting to slip.

 

Harmonic balancer? I have no idea what that is.

 

if its a 3.0 it could very well be your cam syncro. they're known to do that when they're going out. mine did that and i had to replace it

 

It's a 4.0. An 02 with 62,000 miles.

 

ah ok nvm then

 

the harmonic balancer is the pulley that bolts to the crank. there is an inner pulley, a layer of rubber and then an outer pulley the belt rides on. if the rubber starts to separate, on start up the pulleys will slip on the rubber because of the drag trying to get all the other systems driven by the belt up to speed. usually 3-4 seconds. with the engine warm, the rubber most likely expands and doesnt allow for as much slipping, so you dont get a noise.

right now its not going to hurt anything, but be careful. once it lets go, the harmonic balancer wil shift, the belt will come off and you will lose all charging power and the power steering. it can happen at any time as well.

other option is a bad bearing, but it would then squeak constantly.

to test the harmonic ballancer, take a sharpie and draw a line from the outer pulley, across the rubber to the inner. then start it on cold, wait for the squeak to stop then shut off the motor.

if the lines arent lined up anymore, thats the problem. if they are, its somewhere else.
if elsewhere, take off the belt and check any of the pulleys for free spinning. all should spin with little effort.

 

one more option. take wd40, spray the belt with just a little, then start it. if no squeak, its the belt.

 

Thanks for the info 06 Ranger.Sounds like that might be it.Will check.

 

Will i need a puller to remove the harmonic balancer?Or,does it just unbolt with a key in it?

 

Like 06Ranger XLT said, it sounds like your harmonic balancer. I would also check the tensioner and all the other pulleys. I once had an alternator that locked up on me.

 

Turned out to be an easy fix.The harmonic balancer checked out okay.I noticed a small amount of play in the idler pulley.Replaced that and,problem solved.

 

Yep. I'm not sure why ford designed them with a right handed thread...but I had a bad idler on my 97 4.0L and was going to replace it over the weekend last year...doesn't it go on the way home from work friday night and leave me stranded. I took the whole bracket and everything off expecting to find a busted bolt and come to find out the pulley had siezed and literally walked the bolt out of the damn hole. They could have just made it a left handed thread.