Zumkopf

I succeeded in resurrecting the 1998 A8Q (D2) air conditioner. Method:

(1) I screwed up my courage and unscrewed the compressor switch (17mm wrench) from the low pressure line, on driver's side near the strut tower. It turns out there is a Schrader-type valve under the switch.

(2) Screwed a quick-connect low-pressure (smaller) adapter on the Schrader-type valve.

(3) hooked up a standard a/c manifold to the high and low pressure terminals (the high-pressure one being in front of the radiator), hooked the third line to a vacuum pump, and pulled a vacuum for half an hour.

(4) Closed all the valves, unhooked the high pressure line, started the motor, and then fed the system some PAG oil and two cans of refrigerant through the low-pressure adapter (you have to jumper the compressor switch connector to get the compressor clutch to kick in). Ten minutes later the air was ice cold.

(5) unhooked the low pressure line, removed the adapter and replaced the compressor switch.

In other words, I essentially used the normal procedure, only converted the switch to a low pressure access point. For reference, the system's specs call for 8.5 oz. of PAG-46 oil, and 22 oz. of R134a. There will always be some oil in the compressor, so take that into account when adding oil.

That is not of course the book procedure, which calls for using the high pressure port only. But it worked, worked fast, and uses the standard equipment.

Z
1998 Audi A8Q (D2) w/S8 suspension, 144k