mickster

Putting in a new AC Compressor tomorrow. Replacing Drier as well. The system evacuated and refilled flawlessly before the compressor was the culprit!

Anyway--the system was already converted to R134a a while back (late 2000s) and shows no sign of leaking and pulls and holds vacuum. System was 99.9% R134a so no contaminants/residual R12 etc. in the system (1991 S4).

Question-do I need to change the expansion valves (front and rear AC)? If so is there a generic one or specific part number?

Thanks!

Michael

dprantl

Part # 928 573 123 05. It is very cheap, I would replace it regardless. If you have rear A/C, you will have two of them.

Dan
'91 928GT S/C 475hp/460lb.ft

mickster

Thanks-any write up on the rear? Is it in the rear housing (hope so!) Found the one for the front.

Bilal928S4

The rear one is located under the passenger seat.

mickster

Actually under the seat or under the car (accesible from the lift)?

CraigL

The rear expansion valve is located within the AC housing (between the rear seats).
The only thing under the seat is a solenoid valve that allows refrigerant to flow to the rear unit.

There are two hidden screws on the rear of the cover on the AC unit.
Once those screws are removed, there are two flimsy clips that hold the front of the cover to the housing. If you are not careful, it is possible to break these clips. You should search the forum for a thread discussing the rear ac. Nicole was an author, if I recall correctly.

SQLGuy

Since you're getting contradictory information, I'll add my confirmation that it is indeed next to the rear A/C unit (not under the seat, or under the car).

You can see where it goes (it's been removed) in a pic about half way down this thread: https://rennlist.com/forums/928-foru...ver-drier.html

What is under the PS seat is the solenoid that cuts the rear evaporator out of the loop when the rear A/C is off.

mickster

Thanks! Just subscribed to that thread and closing this one.