2002 Pontiac Ram Air Trans Am ac is not cooling properly

[Tim]

Many pages of posts, which I have not read many. Are the inlet and outlet evap tubing under the hood at the case the same temp?

Don't just toss parts at it. Your pressures show you are within range. Have you checked or addressed any reheat issues? Do you know the exact amount of oil in the system at this time?

[dannyual320]

The inlet just after the OT is cool (slightly) to the touch and the outlet feels like ambient temperature.

The oil charge is the original GM installed back in 2001 (it is a 2002 model, though.) There are absolutely no signs of refrigerant/oil leakage anywhere.

[Tim]

So when you put the replacement compressor on? How much oil did you add?

[dannyual320]

So when you put the replacement compressor on? How much oil did you add?

Tim, the compressor and all the other ac parts are factory OEM. Other than add a little refrigerant earlier this summer, nothing on the ac system has ever been touched. I'm the original owner of the car.

I did have trouble with the compressor starting about 8-10 yrs ago in that the evaporator would freeze up on drives longer than an hour. I guess the variable displacement compressor wasn't "variable displacing." I was told on this forum that the only fix was to replace the compressor. Since the ac system back then worked fine otherwise, I decided to live with it since 99% of my drives in this Trans Am are way under an hour.

A19 mentioned a compressor control valve several posts ago. Does that control the variable displacement?

[dannyual320]

Oh. A "L" 9! I apologize for getting this wrong. My eyes just aren't as good for near vision as they used to be! On the other hand, my distant vision has been improving as I've been getting older !

AL9, you've got me sold on trying a new compressor control valve. I just looked up these control valves and I see that one online company sells two different color control valves for my car's compressor:

1. Purple (41psi)
2. Orange (45psi)

Is this the right one from Tim's online store?

https://www.ackits.com/31-55313-control ... trol%20val

[Tim]

Santech list Purple for the 02 5.7L

I can understand if you are just trying to make it better. But if the compressor was never changed. Why mess with what came from the factory? Just asking is all.

[dannyual320]

I can understand if you are just trying to make it better. But if the compressor was never changed. Why mess with what came from the factory? Just asking is all.

Tim, are you saying that I should change out the original control valve with a new purple valve? Do you think that the control valve could be the problem with my ac system?

[Tim]

No. Just saying what vendors list as the OEM CV.

I had a 96 Z28 for a short time. It never cooled well. Not sure about how similar they are. You might be doing the best the system, will do. Way too many pages of posts to read them all. What I have read is your pressures did not seem that far off.

[dannyual320]

No. Just saying what vendors list as the OEM CV.

I had a 96 Z28 for a short time. It never cooled well. Not sure about how similar they are. You might be doing the best the system, will do. Way too many pages of posts to read them all. What I have read is your pressures did not seem that far off.

Tim, yes this is a long thread and I should probably summarize it soon. Other than the evaporator freezing on drives longer than 1 hour, my black Trans Am's ac always cooled very well in the Florida and Texas heat. At the beginning of last summer, during my first couple of ac uses, it seemed to take just a little longer for cold air to come out of the vents. After several uses, the ac seemed to be working normally and I just thought that maybe it needed a "wake up" from not using it during the cooler winter months.

At the beginning of this summer, the "wake up" was much worse. No cool air for quite a while and even then, it didn't get very cold. I started driving with a thermometer in the vent and could only get 55F temps at best. It would take a while to get down to 55F. I never measured the good working OEM vent temperatures but I would guess they were close to 40 degrees.

Even before I recovered the refrigerant several days ago, I couldn't get any cold air. Vent temps were barely lower than ambient. After running the ac for about 10 mins (doors open, fan on high) I got the vent temp down to the mid 70s. Not good.

I've been driving my wife's 2013 Honda CRV and the ac puts out cold air almost immediately after start up. I've also been driving my big, 2001 Ford F250SD crew cab diesel and it too puts out cold air almost immediately. With both of those perfectly working ac systems, I usually end up turning the blower speed down after a short while even when it's 95+F outside.

[Tim]

When it is not working well is when you need to get some pressure readings.

This would have been a good thread for GMtech. But have not seen him around in a while.