Re: A/C 87 325e

[alex.fadeev@xxxxxxxxxxx]

Tony Canike <canike@domain.elided> wrote:
>   The A/C leaks.  Again.  The A/C has been the most problematic system on

> this vehicle, my daily driver for 14 years now (well, when I'm not riding

> the bike.)   I recharged in April and it held for about a week.   System
> was converted to r134a (1998) and both the evaporator (1998) and
condenser
> (1999) were replaced by my local indy shop due to pinholes.
>
> Today I bought a fancy $50 UV leak detection kit from the local auto
chain
> (PepBoys) and looked for old dye stains before doing anything (who knows
> what the shop did or what dye stains they left behind).   I then put a
can
> of dye-only charge and a can of 134a into the system and looked again. I
> feel like one of the guys that CSI TV show with the yellow glasses on!
>
> There appears to be a leak around where the high-side hose block bolts to

> the compressor.  Also there might be a leak at the high-side test port,

Tony
That's also the area where the hi/low pressure switches are mounted. Have
both of them been replaced during the conversion?
R134a runs at a higher before/after compressor pressure difference. The low
switch is liable to cut 12V going to the compressor to keep it from self
destructing (no gas => no lubricating oil). The high switch opens when the
pressure goes above a certain threshold to keep the system from blowing up.
A clogged condenser, a dead auxiliary fan or an overchaged system can lead
to the high pressure switch opening and bleeding some of the R134a out of
the system. You may also have a bad switch or a leaky connection in the
area.

> but I forgot to look there before putting in the dye.  Condensor looks
clean
> I did not tear apart the dash to check out that area around the
evaporator.
>
> I had suspected compressor seals since that's the only major thing that
> wasn't replaced!  So, I have been mentally preparing myself to replace
the
> compressor.  But if it just an o-ring/gasket at the host block joint that

> could save some $$.  But before I think I'm getting off easy let me pose
a
> few questions to the list:
>
>    (Sorry if I'm starting up an old debate - I've been off-list for 5
> months due to travelling...if you want reply offlist and I will summarize

> for the list.)
>
> Will a replacement 134a compressor perform better then the existing
> original factory r12 compressor?

Check with www.koalamotorsports.com
Some E30 years require a new compressor and different hi/low pressure lines
to keep R134a from leaking away. Yours may or may not be one of them.

> Note the system didn't seem to perform as well after the r134a
conversion,
> but it is hard to tell - the system never seemed really good from day
one.

Mine works like clock work (when I don't blow the aux. fan fuses and don't
overheat and overpressurize the system causing the high pressure switch to
bleed some R134a out of the system).

> Might there be shaft seal leaks under the clutch that I can't see?
> Where do compressors usually go bad?

Sorry, can't help you there. Mine is still OE 4+ years after the
conversion.

> Replacement compressors seem to be able to be had for under $400
> (bimmerparts.com - no relation/interest, just the local guy I sometimes
> buy parts from.)   Should I just put a new one in?

No.
Find the real source of the problem before you dump $400+ labor on a guess

alex f

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