Re: Re: R12 to R134a Conversion

From: RLewis7785 (RLewis7785@AOL.COM)
Date: Tue May 19 1998 - 17:49:00 EDT


In a message dated 5/18/98 8:55:28 PM Central Daylight Time,
tonyms@acadiacom.net writes:

<< Saw a conversion kit in autozone for 27 bucks...it was behind the parts
 counter so i didnt get a good look at it but it only looks like you have to
 replace to parts that look like to tubes. I dont know it has got to be more
 to it then that. >>

I put that same kit in the old ladies mazda a few year ago. It was easy, it
has two cylinders of additives, one to keep the dino oil from reacting with
the R134. R134 is only friendly to Synth oil, dino oil doesn't dissolve in it
and therefore doesn't get carried in the refrigerant. The other has synth
oil, and seal conditioners (R134 molecules are 10X smaller than R12, so a non
leaking R12 system may leak like a sieve on R134). The kit also contains the
connector converters to screw over the R12 fittings and allow the use of R134
quick connect style fittings. Overall, my impression of the product was
satisfactory, but I was just buying time. My old R12 system had leaked down,
and I did not have the money to fix it, so I went to this, It cooled OK, but
my compressor failed after a couple of months. I can't say for sure whether
this had anything to do with the R134, since it was rattling badly even before
the conversion and finally blew out a plug on the compressor.

 All things considered, I'd avoid these kits if at all possible, and use them
as a last resort to get by. There are professionals that could probably do a
better job.

Another thing, R134 doesn't have as much cooling capacity as R12 for the same
volume, so if you convert without changing the dynamics of the system (larger
capacity), you will lose a significant amount of cooling.

My understanding of the correct way to convert is to empty the system, change
the accumulator (and the desiccant inside), replace the condenser with a
higher capacity one, remove and drain the oil from the evaporator, remove all
other traces of dino oil wherever it may hide, and to refill the new system
with the correct synthetic oil, and recharge. On vehicles made 10 or so years
ago, it may also be necessary to change all of the hoses, because they cannot
contain the smaller R134 molecules.

Sorry so long...
Richard Lewis
92 LE CC, 318, Auto



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