Questions and Answers
A/C Question
Q. Hello, I have a super simple A/C question for ya. I'm wondering if the A/C on my 1997 Trans Am has enough refrigerant in it and my Haynes manual says to feel the receiver/drier and the input pipe to the expansion valve. The manual says the receiver/drier should feel cool and the input pipe should feel warm. Is this right?
They're both connected! How could the drier be cool and the pipe coming out of it, into the expansion valve be warm. Well on my car, the drier is warm, and the input pipe is as well. The only thing that is cool to the touch is the line coming from the expansion valve back to the compressor. Any thoughts?
A. Feeling lines won't tell you much about the amount of freon in the A/C system. For reasons known only to GM they do not use a sight glass that will tell you at a glance if there is enough freon in the system so the best way to determine if there is enough is to use a set of A/C pressure gauges.
With the gauges properly hooked up and the engine off, the pressure should be, more or less, equal between the high and low pressure sides and above 50 psi. If the pressures are lower than that, then you are low on freon.On the R-12 systems, I used to use a tire pressure gauge to test the pressures but the fittings on a R-134a system won't let you do that.
The only other way to be sure is to have the system completely emptied and charging it with the proper amount of freon. According to federal law, this has to be done by a licensed A/C technician.
Additional Information provided courtesy of ALLDATA
