r134 conversion

["David A. Leonard" <dleonar1@xxxxxxxxxxxx>]

Concerning the R-134 conversion..
I replaced my leaky condenser(system empty all winter) and took it to my 
friendly ac shop.  we pulled a vacuum on the system for 1/2 hour or so, 
then recharged  my 88 735is' system with R134, I believe you use 65% or so 
of the R-12 capacity.  We did nothing to the dryer, hoses, seals, or 
compressor.  This was three years ago.  This may well be the fourth 
season.  Every summer it takes a can or two of R 134 to top off the 
system.  It is cool enough barring high 90's at which point you do need to 
run high and recirc.to maintain a reasonable coolness. It does like moving 
rather than sitting, the airflow helps the cooling.

The AC guy allowed as how most retrofits were drop ins just like this.  We 
did add some of the r-134 oil.

Concerning dryer replacement, he said that it isn't the moisture, it is the 
old oil clogging the dessicant which takes out old dryers.. the moisture 
comes out just fine in a vacuum.

Concerning hose replacement,  I have read that the refrigerant oil in older 
hoses usually forms enough of a seal in the hoses so that the R-134, which 
is a smaller, more leak prone molecule, will stay in the standard hoses.

My  original comressor is bearing up under the strain well.. the car has 
248k miles.

I did replace the failed OEM fan with a 16" aftermarket cheap fan for 
$85.  I also removed the ballast resistor which causes the aux fan to run 
at 1/2 speed when the AC is on.  Mine now runs full blast when the AC is on.

Hope this helps, Dave Leonard

88 735i R134
91 325ic r-12 and not leaking
93 GMC Suburban, converted to R-134 some years ago and still capable of 
cooling beer
92 Buick Roadmonsta r-12 and holding 
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