99 7.3ltr
I replaced all three pulleys,2 on tensioner pulley and one between a/c compressor and alternator,alternator is new to. A new belt and so far 2 a/c compressors all new. When I put new a/c compressor on it was fine for a few days then started to squeal,took it back and got another new a/c compressor,fine for a few days now this one is squealing too. Sounds like the belt is squealing but the belt is tight. Could the belt tensioner be over tightening the belt and making the a/c pulley squeal? Checked the gap on a/c clutch and it has good clearance.

 

Sounds like a loose belt tensioner (is it new?), you have replaced about everything.

 

thats the only thing that I havent replaced,

 

that's the only thing that I havent replaced,hate to replace a good part for another.It seems strong when putting the belt on