The car I have now is my second Camaro... both came stock with A/C, but neither one ever worked. Last week I finally replaced the blower motor (which also never worked in this car), and decided to check the A/C for leaks. The system was already bone dry... either a previous owner drained it at some point or it just slowly lost all its refrigerant over the past 16-17 years. I hooked up a vaccuum pump to the low side on the system and I was at 30 psi vaccuum almost instantly. I let it run for a good half hour to suck out any remaining moisture, then shut it off and left the gauges closed on the system to check for a drain over another half hour. It held the vaccuum, so I charged the system with HotShot R-414b with the engine running, and the compressor starts kicking on and off. It finally stays on as I charge it up to about 35 psi, and voila, I have working A/C in the car!! It has performed flawlessly over the past week or so, and is quite cold. I haven't had any compressor problems as far as the different refrigerant goes, but I realized that I DO need a new alternator now (the lights dim pretty well with the A/C on).

Just thought I'd share the story.

 

Hey, how exactly do you add the R-414b? I have a 91 RS that blows nothing but hot air when the AC is on, and when I have the AC, vent, or defroster on, the car jumps from 500 to 700 RPM whenever the compressor kicks on at engine idle (like at a Red light), producing a bucking sensation to the car. Is there any way to correct that myself without having to take it to an AC shop?

 

Usually, the engine should drop in RPMs when the compressor comes on, unless your car has some kind of regulator to put more gas to the engine when the A/C is on. If your system is empty, your compressor shouldn't come on at all, which would explain the jump in RPMs possibly, if you do have a regulator.

The refrigerant is added just like R-12. You hook up one hose to the tank, which would go to the middle fitting on a set of pressure gauges. Then hook up another house (blue) between the blue gauge and the low side of the system (near the accumulator). Open everything up and fill the system until you have about 34psi I believe. Do this with the car running and the A/C on. You'll see the compressor clutch engage and disengage a few times until there's enough pressure to keep it on.

This is after you pull a vaccuum on the system. You basically get a vaccuum pump, hook up a hose between the pump and the middle fitting on the gauges, and the blue hose again between the blue gauge and the low side of the system. Turn on the pump and you should be at about 30psi vaccuum. If it takes a while to reach 30psi, you have a leak somewhere in the system. Leave the pump on about a half hour to drain the system of any moisture, then close the blue gauge and shut off the pump. The system should hold the vaccuum. Let it sit for another half hour. If there's no change in the pressure, you have no (noticeable) leaks and you can charge the system.

That's all I can really think of now. Maybe someone else can add in a few things, since I've only done this once.