Yet Another E30 A/C R-12 to R-134a problem, HELP!

HELP!! I need SOMEONE who knows A/C and has DONE R-12 to R-134a
conversion on an 80s E30/325e! Here's background and 3 Questions at
the end, please anyone who has insight or can help please do!!

STATUS: Do-it-yourself E30 fanatic with a WORKING (checked re-checked) reman compressor (rebuilt & original to this car) with proper a/c oil-leve, NEW receiver/drier, and new o-ring seals. All just recently
installed. So far no leaks are detected.

PROBLEM: A/c seems to be working normally but ONLY *mildly* cools
(2-4 degree drop at vents at best). At Idle 700-800 RPM, the system
shows 30PSI on the Low pressure side, and nearly 300PSI on the high
pressure side!

I need to know why I have unnaturally "high" pressure on the high side
(I'm told should be around 200-225 or so) and zero-cooling. Here's my
car's A/C History, I'm the SECOND ownwer with a foot-high stack of
maintenance paperwork so I should know:

1987 - BORN! Sold with working R12 system and Nippodenso Compressor and receiver/drier that has HIGH/LOW pressure switches on it.

2000 - Original owner had R-12 system "Upgraded" to 134a by Midas:
Honestly they trashed it. ALL they did was evacuate the freon & oil,
put in new o-rings, and NOT even sure if they changed receiver drier!!
The ONLY new thing they appeared to have put in was the Condenser as
it is only 3 yrs old) This was before I bought the car in late 2001.

NOW - Nippodenso A/C compressor determined to be r134a compliant IF
remanufactured. It was removed and sent to reman facility for TOTAL
rebuild (seals, oil, shaft, everything). It is pretty, silver like
new, and operates TOTALLY normal with no detectable leaks! The young
condenser was totally flushed and cleaned out. New Receiver/Drier
installed with EXISTING pressure switches (both high and low
p-switches).

What I think: Clutch engages fine, all seems fine and I see normal
flow in the rec/drier sight glass. I just get high pressure and
crappy cooling at the vents. To be safe I have not operated the AC.
The compressor clutch remains engaged where on most cars it will
disengage after a few minutes. I think this means I have either
blockage somewhere past the rec/drier, or maybe the high-pressure
switch (or both?) isn't working correctly.

I am planning to replace my expansion valve ("H-valve" near the
evaporator) on a hunch that this may be clogged and is what is causing
the excessive pressure.

My questions are:
1. Does high pressure mean cloggage somewhere past the
receiver/drier??
2. Should I replace my Expansion Valve?
3. Does one need NEW pressure switches on an e30 that is doing 134a? If so where I can find one?

Please help if you can, I don't want to pay $2000 at an a/c rip-off
shop as I have to pay them high labor while they "learn" my old car.
I have friends from out of state with awesome A/c (30 degree drop at
the vents!) so there's hope, no?

Please help if you can, thanks!!

Julian West
E-30 Enthusiast, even with bad A/C

i would like to know the answer to this too.

the air in my E30 is not all that either, kinda really stinks in the summer. wondering what i can do too. . .

E30 PRIDE!
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