Jamie '87 CGT

I'm kinda stumped, but it seems like when I turn on the AC, only cold air blows out of the 2 center vents, and no other vents,the other vents blow, but not like the center, it is somehow designed so that the outside vents just kinda recirculate whats in the cabin while the two centers actaully cool the air?,I have also noticed when i take off from stand still the ac gets warm for a second then cool, could that just be a loose belt? Last summer i just put on new compressor, drier, recharge, and everything is working like it should as far as engine compartment goes, any suggestions?

Dwight V.

A/C cooled air should come out ALL of the dash vents. I would hazard a guess that the outer vents are somehow not opening to the a/c system. How they work though I don't know...cable? Vacuum motor?
I once drove a Vanagon that only blew cold air while it was moving. Not fun, and not right. Can't tell you the cause though.

StormChaser404

All 4 vents should have airflow, but it is NORMAL for the outer ones to have MUCH less airlow. The air will follow the path of least resistance and the center vents are MUCH closer to the blower motor with much less twists & turns. If you really want to even things out, partly close the center vents. The outer vents are the only ones that get heat, so during the winter, you'll likely want to close the center vents all the way. The venting system on the 4k/CGT doesn't use any cables or vacuum tubes to control the dash vents. The floor vents and defroster are cable controlled.

audiqv8

Make sure that the electric fan is working. In addition to keeping the the car from overheating it is also used to cool the condenser. If the fan fail to come on when the AC is on you will have to fix this. The fan help cools the freon as it goes through the condensor (heat exchanger) and help lower the high side pressure. If the high side pressure gets too high then the high pressure switch will disengsge the compressor clutch. There is also a low pressure switch which protects the compressor when there is not enough freon in the system and will also disengage the AC compressor clutch if the pressure is too low.

When the car is moving air passes through the condensor without the aid of a fan, but when is it standing still the fan is required to move air through the condensor.

StormChaser404

Does anybody know what the correct high side pressure should be? Should it be higher if converted to R134a? At what pressure does the high pressure switch cut out the system?

Dave

eehokie

Check aircondition.com. I found this in my search:
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There are too many variables to use to "set" temp pressure.. If you have a factory system, best to charge by weight and tweak the system a few ounces +/= <B>If you retrofit, start at 2.2 times the ambient and monitor vent temps while "trying" to remain in the 2.2 to 2.5 times ambient..</B>If you want a chart, here is what Interdynamics recommends.. I personally would not use it, but it's your car...: The high sides aren't too bad, but I would not want 50psi low sides

The following is the Ambient Temp/Pressure for R-134a;

<B>Ambient
Temp Low Side High Side
(F) (psi) (psi)</B>

65 25 - 35 135 - 155
70 35 - 40 145 - 160
75 35 - 45 150 - 170
80 40 - 50 175 - 210
85 45 - 55 225 - 250
90 45 - 55 250 - 270
95 50 - 55 275 - 300
100 50 - 55 315 - 325
105 50 - 55 330 - 335
110 50 - 55 340 - 345