AC problems 98 GT

Ga30517 · 06-25-2007, 10:46 PM

I have a manual ac, with no dual climate, I had the ac charged. I am getting cool air from the passenger vent, warm from the center, and almost hot from the driver when the dial is set to the coldest setting. When I put the dial to heat it seems to work normally. Could someone please point me in the right direction, and possibly schematics of the repair?

Brian

BNaylor · 06-28-2007, 06:23 AM

Welcome to AF.

What was the charge reading on the low side port? Uneven cooling across the evaporator on a manual HVAC system is typically caused by a low refrigerant charge. The charge should correspond to the ambient temperature.

Ga30517 · 06-28-2007, 11:42 AM

I really dont know, I had it done at the dealership, they said it was fine. They said without tearing everything apart (and charging me about $3000) all they could do was guesstimate. They told me it was probally something in the "heater box" which I assume is the housing for the heater core. I didn't think that sounded right because I figured the heater core was the core of the heating system and not really related to the ac. I could tell you anything about building or repairing a house or building but I don't know much about auto repair. I'm sure he picked up on it and wanted to milk it for what its worth. On an un related topic how do I post pictures on this site?

richtazz · 06-28-2007, 04:25 PM

Sounds like you need to find a new dealer. I agree with bnaylor, that it sounds like low refrigerant charge. It could be a partially blocked evap core, due to mold, mildew or debris.

gtp'n · 06-29-2007, 02:37 PM

I had the same thing happen to me the other day. I took it to the shop because I had the same symptoms that you discribe. The presure on the high and low side were fine. I took it to the shop and they told me that there was debrie in the orfice. The cleaned the screens and it is running like new. total cost was 88 dollars for labor.

BNaylor · 06-29-2007, 08:36 PM

Based on my experiences with the Harrison V5/VDOT/TXV system a restricted orifice will show as low suction side pressure and lower than normal high side pressure so technically the pressure readings will not be normal. When the compressor kicks in, the suction against the restricted orifice will cause the compressor to quickly cycle out. After compressor disengagement, the rise in suction side pressure will usually be very slow. Rapid compressor disengagement and slow engagement may indicate a clogged orifice. A clogged orifice tube will starve a compressor of oil.

If you are getting excessive contaminants at the orifice tube then it may be signs of a compressor breaking down or failing usually caused by running with a low refrigerant charge in the first place. The contaminants are typically metal particles. Called the "Black Death." The pic below shows a contaminated/clogged orifice filter.

A/C repair shops will clean or change the orifice tube filter routinely as a matter of procedure but alot of times all the system needed was an evacuation and recharge to include the proper amount R134a refrigerant and compressor PAG oil.

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