Squealing noise from engine......

[Jtcaudle15]

I have a 2008 Denali with 78k on it. Recently when i start it cold I get a squeal similar to a belt noise for about 10 min then stops. I tried spraying wd-40 on belt and seemed to work. With that I replaces serpentine belt, tensioner pully and assembly, and a/c tensioner. Noise is still there. Any other ideas of what I could check?

All feedback greatly appreciated!!

 

[OR VietVet]

On a cold start take each belt off separately and see if noise goes away and if does then need to check for the noise at whatever spins with that belt. I hope you used good quality belts and the AC Delco tensioners and idler. It is best if you have an inexpensive mechanic's stethoscope to listen with.

 

[Cmicasa the Great XvX]

Turn on AC on and see if noise persists or goes away. Sounds like AC bearing

 

[bottomline2000]

Check the idler pulleys and make sure they are tight. Had this problem recently on my GTO and the fix was to simply tighten the ac tensioner bracket. I wouldn't spray wd40 on something designed not to slip. May want to clean yours belts to get rid of the wd40 as this may now be your problem.

Long story short your initial fix may have been free if u tighten everything first to fix the alignment of the belts.