Does anyone have a picture of the low pressure A/C port on a '87 951 with the original factory A/C setup ? I'm pretty sure it is down on the compressor somewhere.

 

I have no pics, but on my 87na, it was the hose going to the compressor rather than on the compressor itself -- accessible from under the car. The high pressure side is the one that's accessible from the top of the car, under the hood.

 

Joe, yes, I saw a port on a U-shaped pipe right beside the compressor (it connects to the compressor). The port is upside down, facing the ground. Is that the one ?

What should the pressure be on the low-pressure side, while it's running, if the charge is ok?

 

Yep -- sounds like the one. There should be plastic cap over it.

I can't remember off the top of my head what the correct pressure is -- I did it last year and found the info using search. I used a gauge I got at PepBoys with pre-color coded indicators. I kinda remember it being around 40lbs or so but not sure.... Make sure you refill with R12 refrigerant. This is also a handy website for AC system: http://www.griffiths.com/achelp/achelp1.htm