Re: 88 325ic AC Question

[Henri Baccouche <henrib@xxxxxxxxxxxx>]

I read the trade magazines we get at the shop........and  I agree there seems
to be to alot of misinformation.

Most of these conversions work......but they do not last.

The R12 hoses leak all year round because the R134a is a smaller
molecule......hence the need for new barrier hoses.
The tolerances on 134a compressors has to be
tighter and more precise because the lubrication of the compressor is more
difficult.  R134a doesn't carry the oil like R12 does. R12 compressor units
work, but the evidence points to diminshed service life especially on high
revving engines......Some of the BMW Behr compressors are not compatible
supposedly because they do use R134a grade seals. However, I put it to you
that ALL R12 compressors are not a good way to go with R134a  period.

The R12 condensers on E30's are marginal to begin with R12, and  with the
added heat extraction needed by R134a...... on a hot101+degree  day.
Fuggetaboutit......

Oh, it will work ..........and you'll evacuate and recharge annually.

Btw, I see expansion valve clogged with rust all the time on E30's.

I thought you wanted to do it properly.......

Regards,
Henri

ToMoyer@domain.elided wrote:

> Henri,
>   Sounds as though you have been talking to the misinformed.  First of all,
> it is very safe to say that on a 1988 325ic the compressor IS R-134A
> compatible (that is if it is the original or original replacement), most
> Bosche compressors dating back to 1984 ARE R-134A compatible (just take the
> compressor number to a BMW Dealer and they will tell you if it is R-134A
> compatible or not as they have a complete list).  New hoses?  Not if they
> are not damaged or otherwise in need of replacement.  New expansion valve?
> Again, not unless it is not working properly and needs to be replaced.  The
> receiver/dryer MUST be replaced, about $60.00 (note:  if your system has
> both a Low Pressure Switch AND a High Pressure switch receiver/dryer,
> replace it with the same type - DO NOT replace it with a single switch
> receiver/dryer unless you want the system to freeze up).  Change the
> condenser?  No need to, the condenser is a heat exchanger and the original
> one will work just fine as long as it is not damaged.  Indeed the newer
> R-134A systems have a slightly larger condenser, but doing a comparison on
> an older properly working system with R-12 Freon and the same system with
> R-134A Refrigerant there was no more than 2 degrees difference when
> measured at the same outside temperature and humidity.
>
> happy motoring,
> tom
> BMWCCA Member
> ASE Certified Tech
> '84 318i converted to R-134A for 3 years
> '85 318i converted to R-134A for 3 years
> '91 318is still R-12 because it doesn't need recharging but will be
> converted

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