AC Stem Valve??

[vesnyder]

What is the trick to turning the stem valve on the York style AC compressor? I am trying to charge my AC and need to turn the valve to fill with coolant. Tried a 1/4" drive socket (the drive end) with an allen wrench in the opposite end. Fits real good but still seems to be rounding the square end? I am currently soaking with PB Blaster, but thought I would ping the board before I totally round off the valve stem??

[Jim Sims]

Are you turning the stem the proper direction? These are typically backseated valves so to put them in the charging postion the valve is turned 1-1/2 to 2 turns inward (turn clockwise looking at stem). Jim

[vesnyder]

Jim - Thanks, I was turning in the opposite direction? Do I back out all the way to reseal then?

[Jim Sims]

Yes, after servicing (charging) turn the stem CCW to close the valve on the back seat. Closed on the back seat is the normal position of the valve during A/C operation. Jim

[vesnyder]

Jim - Thanks for the advice. Got the system charged and it is blowing cold, but I still do not see any sign of coolant in the view window in the evaporator? The evaporator (I think that is what it is called?) gets real hot, but according to the guys at Duracool I should see some bubbling through the window?? Any ideas?

[ruf-porsche]

If it is blowing cold I wouldn't worry about seeing bubble in the drier/receiver. No bubble can mean one of three things

1. The system is correctly charge
2. The system is over charge
3. The system is empty.

[Jim Sims]

I hope you have the deck lid closed while you are running (including during charging) as you must have air (the engine fan pulls air over the condenser and one should have the engine running at 2000 rpm during charging) moving over the condenser in the deck lid otherwise it will get too hot and the pressures can be too high. With the deck lid up there is the danger of blowing hoses, ruining the compressor and most important of all personal injury. One really needs to charge with a refrigeration harness to do it properly. Jim

[ruf-porsche]

Hey Jim

That's why I tell people to bring it to an expert if they don't know what they are doing when it comes to the a/c system in their Porsche. It's great to offer advice to newbie, but some people aren't that mechanically incline and it just take one person to connect a can of refrigerant to the high side instead of the low side to wish that maybe we shouldn't have encorage him to repair his a/c.

My father who was a certified mechanic taught me about auto a/c. He was there to tell me not only how to work on a/c system, but the theory behind a/c system and the necessary precaution when servicing a/c system.

[cadman]

Hi I'm new to the forum and also 7 years late on this discussion. I have a 1978 911 SC with the York Compressor. I have tried turning the stem valve clockwise to open it but can't budge the valve. I'm using a 1/4" 8 point socket, which fits but has some play in it. and I'm worried about rounding over the stem if I exert to much force. My questions are:

1. What are you guys using to turn the stem valve?
2. Can WD40 be sprayed on the valve?
3. Can the stem valve be replaced on the York compressor?

Thanks

Chuck

[pj.1]

Hi, I'm wondering if anyone has advice for a stuck recharge stem valve? I, too, first tried turning counterclockwise. When I found that clockwise opens the valve for recharging, I tried turning clockwise, but it won't budge.
Does anyone have any suggestions?
(1980 911 SC)
Thanks!
- Paul

[kuehl]

Originally Posted by vesnyder

Jim - Got the system charged and it is blowing cold, but I still do not see any sign of coolant in the view window in the DRIER The DRIER gets real hot, but according to the guys at Duracool I should see some bubbling through the window?? Any ideas?

You should be observing the pressures vs. ambient temperatures while charging and comparing that to amount of refrigerant. Ask Duraxxxx
for a copy of their pressures and temperatures chart.