A/C help

tsjeepcj

tsjeepcj

Well-Known Member
Joined
Mar 20, 2005
Location
charlotte
I have an 03 duramax and am having a/c issues. The air has never really blown cold. I got a set of manifold gauges and got the following readings.

Air temp was 90 degrees

I measured the high and low side before starting the truck to see if the high and low side had equalized. I got the low side at 105 and high side at 10. After starting the truck and getting it up to temp I got the low pressure side to 53 and high pressure to 145. I realize that the compressor is likely bad causing the high side not to build, but am wondering why the high and low side had not equalized prior to starting the truck? I want to make sure that isn't an indication that the condenser has gone bad. I've already ordered the compressor, drier, and orifice tube but would hate to get all that changed out only to find out the condenser is bad too..

Any ideas?? Suggestions?

Thanks in advance

Tim
 
I would question the initial pressure readings. Could be a bad gauge or hose connector not opening valve. I have a high side hose I have to put extra down force to open valve. If you're not reading pressures correctly it's difficult to diagnos. Your problem with the Ac could be with the air doors in dash
 
I'm going to use some residential a/c theory here. If the a/c system uses a non bleed txv then it's normal for the liquid line to hold working pressure after the unit is off. It's an efficiency thing, not having to recompress the liquid line. I have very recently found that cars even use txv so again this is theory. Now back to the main topic. Your liquid line pressure could be low because of a low refrigerant level. I would add some while the reading the gauges and see what the pressures do. ONLY ADD REFRIGERANT USING THE KNOB ON THE BLUE GAUGE SIDE. YOU CAN'T ADD ON THE RED SIDE AND YOU COULD BLOW THE CAN OF REFRIGERANT UP. Don't use anything that has leak stop in it either.
 
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