jmastera

The AC in my 95 Tahoe recently stopped working so I decided to try an fix it myself. While reading the Hayes manual I purchased I found it to be a litte lacking in the area of AC. A friend said that I may be able to do it myself and to purchase either R12 or R134a and a recharge kit (my tahoe takes R134a). After finding what I believe to be the Low Pressure valve (I can see 2 similar valves but the kit only fits on 1) and connecting the kit with the recharge canister attached (with the ignition on, the ac on and the fan on high) I realized that the contents of the can was still full. After pulling off the kit I felt and heard air coming out of the low pressure vavle.

From what I can tell there is pressure on both the Low and High vavles. Is this normal? Could it be an issue with the Climate Control Panel not switching on the AC since there is pressure still in the compressor?

Sorry for the log drawn out question. I am a computer nerd not a car guy, but have managed to walk myself through a couple of low level things in the past and was hoping this would be a similar situation.

kcb37

Did your kit come with a guage? If so did you check to see how much pressure you had before you put coolant in? I haven't done this for about a year, but excess left in the can, and fluid/gas moving thru the lines with the air condisioner on will both cause this. Was the sound of air momentarty, or did it sound like you just pulled a nail out of a tire and let all the air out? If it was momentary you should be fine. And yes while running you will have some pressure on the low side. If you had to recharge it without letting old coolant out you more than likely have a leak.

jmastera

Unfortunately the kit did not come with a gauge. I heard the sound when I realized that the contents of the can were not changing and I removed the kit from the Low Pressure valve. The sound was more along the lines of lets say when you pump up a basketball or football too much and then remove the needle; it was a quick "pssst" sound. I could kind of hear it when putting the kit on the valve as well but it was more muted.

I have not let any coolant out of the ac system at all at this time. My wife drives the vehicle most of the time and one day told me that the ac had gone out so I figured it needed a recharge since it is a 95 and I have not done any work to the ac and the previous owner lacked in general maintenance skills. Now with there being pressure in the line still I was thinking maybe the switch has gone out and the compressor is not turning on, or maybe the compressor is bad, or both. While examining my garage floor I only see the motor oil that leaked around the time she told me the ac went out so I don't believe I have a leak in the ac, but I could be wrong.

Worst case scenario, what does it normally cost to have the ac system looked at/fixed.

kcb37

I'm sorry but I should have added this, when you add it you are supposed to hold the can upside down. You will want to be careful as to much coolant will keep it from working very well too. Check to make sure the compressor is plugged in tight and has clean connections. If you have a multimeter you can also test the wires to see if you have power. Check your fuses, if it is not any of that I would guess your contorls. They have a little "computer mother board looking thing on them" I don't know how much that cost either.
You will have to have a book to check that and it may not tell you how to. I don't know for sure.