Air conditioner issue

[kitkat22]

My A/C started blowing hot air today and my first thought was it needed a recharge. Wandered over to my neighborhood friendly checkers and grabbed a kit. Obviously, I needed to check the pressure before refilling so I attach the gauge and turn the car on. Idling for a little brought the gauge down into the "normal" range, but then it immediately shot up into the red, indicating too much pressure. It would slowly head back down and get close to hitting green again before shooting right back up. I can hear the compressor go each time it shoots up. I clearly decided not to do the recharge, but now I'm a little confused what to do. As far as I know, nobody has recharged the A/C since we bought the car in 2003, which is why I was thinking the refrigerant is low.

2003 Chevrolet Malibu with 95,000 miles on it. It's the 3.1 liter engine (I think there's only one type) with the no mods and basic trim (not the LT)

Edit: I'm in phoenix, AZ so ambient temp is definitely on the toasty side.

 

[herm0016]

there is a bypass valve that opens when the compressor is on or off... i don't remember what it is called at the moment, but that could be your problem. had to replace that valve on the Chevelle.

edit: the valve was controlled by the temperature of the refergerent on the hot side.

 

[kitkat22]

Originally posted by: herm0016
there is a bypass valve that opens when the compressor is on or off... i don't remember what it is called at the moment, but that could be your problem. had to replace that valve on the Chevelle.

edit: the valve was controlled by the temperature of the refergerent on the hot side.

How do I tell if this is the issue?

 

[xgsound]

In cases where the low pressure goes into the red with the compressor running it's usually the "expansion valve" that has clogged. Here's a link at advance auto for a 2003 Malibu.
http://shop.advanceautoparts.c...ACPTAMS__air%20cond___

This is not guarenteed, but at $2.99 it's not much of a risk. Unfortunately, the system should be evacuated to vacumn before recharge anytime it's opened to the atmosphere or corrosion will be certain in short order. I would try the part and a cheap recharge kit first. If it works get the evacuation/ recharge done. If not, you're at the mercy of the repair guys, which is where you already are.


Jim