I have a 98 Blazer and i have changed belt tentioners ,idler and belts,also alternator .Still i get squealing when my truck is running. can anyone tell me what could be causing this noise?Help please:

 

What brand belt are you using? I think it can matter.

 

this will cure it

 

Here's a trick from someone that loves working on cars, not a certified mechanic but certified in driveway mechanics. Get a glass of water, have the engine on and pour just a little bit onto the belt itself. If the squeaking stops, it's a belt. If not, it's a pulley,