I have replaced the idler and the tension-er, jw if anyone knows a good way to identify what is squeaking.

99 expedition 5.4 4w

 

When the belt is removed, spin each pulley by hand. Could just be a light squeak you are looking for which at higher rpms becomes louder. I would check the alternator, Idler and tensioner. Is the belt new? Check for signs on the back side of the belt for misalignment. And last, but not least.... and probably most expensive would be the ac pulley/clutches.

 

i alreay turned them all by hand and they were fine replaced idler and tensioner

 

Let it run for a minute without the belt on , if the sound is not there it has to be a
front end component,water pump, fan clutch. You have already eliminated the
tensioner and idler. Sure its not the a\c?

 

I'm betting on the alternator, putting on a Gatorback belt is a big help as well.

 

I had a similar issue with my Xterra. I ended up spending the $$$ on a Gatorback belt. Well worth the $40-$50. Took care of the issue once and for all.

 

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