R-134a Specs Request ('88 5KS)

["Christopher Ritchie" <cjr1@gte.net>]

ml wrote:

>We are changing over a 1988 5KS. Short questions. What kind of oil and
>how much? How much R-134a?

Just did this on mine.  The R-12 amount for this system is 38 ounces.  Most
retrofitters recommend that you use 80% to 85% of that amount for R-134a.
Overfilling is _not_ better.

I used the polyol ester that came with the $30 kit I bought from Pep Boys.
I used ester oil because I did not flush the system.  I believe the general
consensus is that PAG oil is better, but you need to get all the old oil out
as PAG is not compatible with the R-12 oil.  I think about 8 ounces of ester
oil came with the kit.

I also did not vacuum the system before charging with the R-134a.  And I did
not replace the accumulator/drier/reservoir.  This is the "cob job" way of
retrofitting.  But it works great on my '88 5KS.  It seems that A/C system
is robust enough to tolerate this.

If you want to be able to get an R-134a gauge on the high side line fitting
in front of the evaporator, you will need to use a 90 degree fitting (~$15).
The straight one that comes in the kits will protrude too far forward for
you to get the usual quick connect fitting on it.  That, and an extra can of
R-134a (~$6) is all you will need to buy to do an approved retrofit.  Of
course, if you never intend to measure the high side pressure, you would not
put the R-134a fitting on there.

The Bentley says to charge the system at the low pressure cut out switch.
You can also charge at the Schrader valve right on the Nippondenso
compressor.  The straight ahead R-134a fitting that comes with the kit will
fit there and allow you enough access to get the charge hose on.

http://www.delanet.com/~pparish/ is a good site for this.

http://www.aircondition.com/wwwboard/retrofitting for a bulletin board on
retrofitting.