A/C no longer works after being serviced
 

First off, the a/c in the 944S is still R12 and it has always worked since I've owned it. It started blowing cool air, not cold air a few weeks ago. I took it to a Valvoline a couple of weeks ago and they ran a pressure test on it. It passed the pressure test so they recharged it and it was working great again. When the service man disconnected the line from the port by the strut tower (high side?) he lost an awful lot of refrigerant. So much that he mentioned it and said if it doesn't seem as cold as it should bring it back and he'll add more. Well it didn't seem as cold as it should so today I brought it back. A different service tech was there and he went to add more and he charged through the port by the strut tower. Now the car blows warm air, the a/c simply doesn't work but the compressor is running. He said he didn't know why it's not working now and to bring the car back when the mananger is around. Is my a/c ruined or can they pull it all out and charge it back up?

No, it is not ruined.
The couplings from the service machine need to be unthreaded quickly, or the refrigerant will escape when the inner needle is still depressing the fitting, but the coupler has not been completely removed. It will require more refrigerant to function properly. The compressor will turn as long as there is enough pressure to trip the low pressure switch (aprox. 20psi) but you must have enough refrigerant for a proper pressure change from compression/expansion to function (usually 60-70 lbs on the low side).

Hope it helps!
-Nick

He may have charged it on the wrong port and caused the refrigerant to be pumped back into the refrigerant tank. That could be the high pressure side because I know, the low pressure port on my S2 is under the car by the compressor.

I agree, I have an 87 and my high side port is on the top by the strut. The low side is right by the compressor and is accessed from under the car. Easy to remember, high side on top, low side bottom of car. You have to charge from the low side port. I just charged mine myself last month.I would take it back and have them do it right.

still need to let the pressures equalize before removing the fittings.

The last thing I would do is take the car back to them. You might want to take a receipt to them, but no fricken way should the car go.

Where is the refrigerant tank you are talking about?

I took the car back and the store manager did a service on it. He ran out of r12 after putting in 23oz, so only 2/3 full. It blows pretty cold though, should be colder however. Because he ran out of freon he gave me a full refund. But now I still need to get another 10 oz. in there. Thanks for all the help. Maybe I'll take that epa 609 test or whatever number it is and buy some r12 to throw in rather than take it to another place.

You can buy and use freeze 12 on ebay. It is a r12 replacement. Many here including myself have had good luck with it. Use the search in the forum.

The tank I am talking about is where the refrigerant is stored and the shops buy them in 30 lb tanks or cylinders. ;)

I looked into freeze 12 along w/ other drop ins a few years back and I have a friend who uses it because he turns cars often. I just never chose to use it. But thanks.

So where did the 10oz of R12 go? Let me try to fathom what you experienced. You took your car in and they checked out the a/c system. They reclaimed what you had left in it, lost a bit in the process, then gave it back and that's it? I hope I'm missing something, because it sounds to me like you got ripped off if you spent a dime.

For the past two years I've been suspecting my freon level to be gradually getting lower. Compressor cycling more frequently and bubbles in the sight glass. A couple weeks ago it was barely cooling. Took it in, checked for leaks, filled w/ freon, lost a lot when he removed the line from the high side. It was blowing cold but not as cold as I thought it should be which I chalked up to the loss of refrigerant when removing the line. Took it back in to have them add more, apparently he hooked to the high side and removed all the refrigerant. Today they added r12 and it is as cold as the after my first visit to them. So initially I spend some dimes and now I got my dimes back and my air is colder than it was when i took it in the first time. Hell, I was lucky they worked on it at all because the 1st two shops I took it to that have r12 wouldn't work on Porsches.

ac is ac.

even taking the line off the hi side showing over 200 psi isn't going to drain everything unless the fitting was loosened and the schraeder valve depressed and the guy walked off to get a cup of coffee.

the loss should have been minimal, not over 30 oz's.

That is correct, disconnecting the hose from the high side will not loose a lot of refrigerant but sometimes the hoses are too long and can hold significant amount of liquid refrigerant enough to lose some cooling capacity.

The high side after the condenser is high pressure liquid and when the service port is opened, the hp liquid will be pushed out and collected in the storage tank just like recovering the refrigerant from the system. This happened when the tech hooked up the charging line to the high pressure side and opened the high pressure service valve. This was how the system lost the refrigerant charge the second time he brought the car in to get the a/c checked out.

you don't charge thru the hi side, it's only a point of reference on the manifold gage, so you don't over charge the system.

what's lost in the hoses doesn't matter, it's how much leaks thru the valve in the charging port.

i was schooled in charging the lo side.

on/off with both fittings makes for a mini loss of coolant, r12 or 134, as long as the tech knows what he's doing, which wasn't the case here.

The case here was the tech accidentally hooked up the charging hose on the high pressure side. This caused some liquid refrigerant (take note: high pressure liquid) to flow back (due to high pressure) into the refrigerant storage tank. So the system lost a significant amount thus lost in cooling capacity.