20002 1500HD Have had for 22 months, and have 36550 miles on it. Started it up this afternoon and heard a whirring racket from the A/C area. Drove it to the closest service department. The noise was off and on going into town. Luckily it made it while the service manager listened to it. He thought it was being caused by high pressure in the compressor. From this part on I am not quite sure what he said. But he thought it was causing my idler to slip?

Drove 10 more miles to the dealer I bought from and nary a noise on the way or up there. Very light noise occasionally later. Stops immediately when I shut the A/C down, but does not last long anyway.

The early noise would last about 5 seconds at a time and was very loud. The later ones were not very loud at all.

Anybody had this problem or a friend with the problem? And I plan to take in next week and leave it with them. The dealer service manager was out. And it would not do anything up there.

Everything is stock, and have had no work done to this truck.


Thanks,

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If it is being caused by high pressure, it will be its worst when it is hot outside and inside is hot too. You may aslo have a bit of premature compressor wear too.

The noise sounds like a small airratchet or rivit gun
going off. And I think it is my high pressure relief
lifting. Does this sound right to any of you?

I posted a question in the Ask the Tech's forum about a squealing noise coming from under the hood, it went unaswered. Almost sounded like a belt squeal, but more metallic, and usually on decelleration. Well, 3 weeks later (last week) my upper AC line blew and so did my AC Compressor. My guess is they were related. I just got it back so I dont have much time on it, but I havent heard the squealing anymore since it was fixed. I don't know if your AC is the same as whats on the duramax, but if it is, I hope you don't have it blow like mine did.

Once I get on the road, it is not sounding. Maybe my imagination but it feels like it is blowing colder air right now. Wonder if that is an indication of lower suction pressure? Or just the lower than usual humidity here right now. And I am pretty much equipment challenged, and don't know if it is the same unit or not.


As Snowman said, it is worse when all is hot. Still plan on leaving it in Angleton Monday morning or Monday afternoon.

Repaired. They replaced the compressor. Working great and
no noises of any type.

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