Squeal under load

[0V3RC10CK3D]

Ever since it got cold / started raining here whenever I turn on my car ( when its cold / has rained / caused condensation ) there will be a slight....belt squeal? Then it'll go away and I wont hear it again unless I compression break the engine...even slightly while the engine is still cold, then i'll hear it squeal again for maybe 3-4 seconds.

After everything warms up I don't hear this and I didn't hear it all summer or if it's sunny outside.

Ideas? Why when I downshift?

 

[Ishodu]

Sounds like it could be a slipping belt.

 

[itwonder]

Check the tension of your A/C compressor / alternator belt. Tighten it so when you twist the belt in the middle of its longest span, grasping it with your thumb and index finger, you can twist it no more than 1/4 turn with moderate effort. With heavy pressure, you may be able to twist it 1/2 turn. Or get a belt tension gauge. If it has slipped a lot, the belt may be glazed and require replacement to eliminate the noise.