My friend'* VW Beetle is blowing hot air with the air conditioning on. I hooked up my recharge kit, and watched the needle shoot up well into the red zone (70-100 psi, normal is 25-45).

How can I let out some of the refrigerant? I imagine it'* a lot like depressurizing a football or a fuel rail — put a rag over the Schrader valve, and push the pin in the center. Correct?

1st MAJOR question, was that pressure reading when the compressor was actually running? If the compressor is not turning on, that sounds about right for the system being at rest.

Yes, the compressor was on.

If you push in the pin, yes it will vent off pressure.

Thought so. Just making sure there aren't any special safety procedures that I should learn.

Naw, Should be gas not liquid. I believe it would still blow cold if overcharged and wonder if something else isn't right.

Well, I let off a little bit of pressure, and she noticed that the A/C was slightly cooler. Google seems to agree.

Of course, I'm more worried about how it got overcharged in the first place; she says that it may have been one of those quick oil change places a couple years ago, because it started about that time. Regardless, I'll report back.

If it was overcharged, it may cause compressor cycling due to an overpressure condition. Are you checking the high and low side pressures, because there may be a bigger issue here.

Not an AC guru, so if it made it better, cool. I'm the "if it stops coming out cold, throw in a can of all in one." And if that doesn;t do it, go with two. Never had that cause hot air to blow, but prolly just lucky, or not have gone to far over. So far so good w/ the GXP, still blowing ice cold with initial charge.

There'* another possibility as well. That high of an overcharge, should have been a problem over 2 years. It'* possible the system was charged properly and part of the system is having an issue that is causing the low side to have high pressure. Been there..had this happen. In my case the compressor went out.

Another thing to keep in mind when discharging an AC system is that the pag oil is corrosive and acidic. You do not want to get it on any part of your skin or the car.