ac shudder question

[rddaves54]

I have a 2002 Tahoe and I have a shudder when the air is kicking on and it sound like a little tweeting bird under the dash on the heater core side, the tweeting sound only lasts a moment or two.

I have not had time to look under hood yet and check it out but does that sound like the air compressor is going out.

I am asking before I go out tomorrow and start to check it all out. I thought maybe this has occurred to someone and you can help me and save me some time and looking.

[BBC Chevy Man]

Sounds like your belt may be getting worn and slipping when the compressor kicks in.

[rddaves54]

I looked under the hood today to check ac compressor noise. I hear the ac compressor making noise when I rev up engine. It is the compressor because when I turn ac off the noise stops.

Could this be the clutch or is the compressor going bad, how would I check to see which is making the noise? It is still cooling.

[BBC Chevy Man]

Could be the clutch but when you turn on the air conditioning the engine has more drag and this could cause the sudden slip of the belt causing a noise like you have. Belts are not expensive and it doesn't hurt if you do preventative maintenance for further down the road. A way to check if the belt is slipping is while its running and the noise is there spray some belt dressing or even a lubricant such as wd-40 and see if the noise goes away. If it does it's time to change the belt.

[truckdude239]

do not spray wd 40 on any belts it will cause them to slip

[rddaves54]

I replaced the belt and no more noise. Thanks I have never heard a noise like this belt made before.

[truckdude239]

yeah the belt gets wore out the new belts dont crack but wear more like tires do so when it gets about time to replace them they dont rubber have enough left to grap the pulleys right so when you put a lot on them the chirp or squeal