Hi. My mom has a 2008 Chevy Uplander van with ~25,000 miles on it. Recently, the air conditioning system seemed to be blowing warmer than usual air. The problem continued to increase the longer we drove it, to the point that it is almost worthless to run the AC. If we drive for more than 30 miles or so however, it seems to start cooling, but nowhere near what it should, or did before this started happening. We have taken it to a few different dealerships here in town and they have yet to find anything wrong with it. They replaced a valve in the system (I believe it was some sort of expansion valve but it had a different name) and that seemed to help a little bit, but it was still no where near as good as it was previously. The current dealership we have it at has had the van for almost 2 full weeks and has yet to find anything significantly wrong with it. I was hoping maybe someone had any tips or knew of any known issues with the AC systems in these vans. Any info would be appreciated.

Thanks

GM usually uses a CCOT system meaning clutch cycling + orifice tube type. If Low cut out is set too low it could freeze up and the ice won't behave as cooling but would again later at a certain stage. If you shut system down - wait a few minutes and it works again for a while that's likely. Pressures would show this. Either way it's under warranty so keep at them about this,

T
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Tom Greenleaf - MetroWest, Boston
http://acsource.net/acforum/index.php

Would you be looking for the pressures while it was shut off, right before, or right after the shut off? And is this something most technicians would look for?

Static pressures just tell if any refrigerant is in the system. Operating pressures lead to where a problem could be and can tell if system is too full or too low. Need both #s with compressor known running if it will (see outer hub move) with a raised idle - say 1,500 or so with A/C on full blast,

T
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Tom Greenleaf - MetroWest, Boston
http://acsource.net/acforum/index.php

Just thought of what might confuse techs on such a new vehicle........... If this uses a cabin air filter it could be the problem! If airflow is slow that would be a clue. Owner's manual should be specific on how to check or replace it. Still at the age the vehicle would have to have been exposed to some serious dust or something for it to be that dirty so soon IMO,

T
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Tom Greenleaf - MetroWest, Boston
http://acsource.net/acforum/index.php

Well I believe it was a rental vehicle before she bought it, so no telling where it had gone through. So air filter could be one thing. With that 1,500 pressure count, I'm assuming that would be on the high side?

One other thing i forgot to mention in my first post: the driver vent seems to be warmer than the other front air vents. Don't know if that has anything to do with what you recommended, just thought I should mention that as well.

Thanks for the fast replies. I'll get with the technician next week and see if he has tried looking into any of this.