'90 LS400 - R12 to R134 A/C Conversion

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Chip L - 17 Apr 2006 02:06 GMT

'90 LS400 240,000miles

With no A/C blowing, I recently converted the refrigerant from R12 to
R134. The system still does not blow cold. Dealership says compressor
is gone. Worked fine in the fall. While investigating rebuilt OEM
compessors, I read some posts re: the upgraded R134 system working at
different pressure than the R12 system and the original A/C pressure
valve (which controls the compressor) may not work when the system is
converted to R134.

Any merit to this? Should the original pressure switch work properly
in a converted A/C system?

Thx
Chip L

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Ray O - 17 Apr 2006 02:35 GMT

> '90 LS400 240,000miles
>
[quoted text clipped - 11 lines]
> Thx
> Chip L

The process of converting from R-12 tro R-134A is more than just filling the
system with 134-A. Besides evacuating the system and draining all of the
old oil, you need to replace the receiver-drier.

Here is a pretty thorough description of the process:
http://www.dmcnews.com/Techsection/r134.html

Signature

Ray O
(correct punctuation to reply)

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mrcheerful . - 18 Apr 2006 08:38 GMT

>> '90 LS400 240,000miles
>>
[quoted text clipped - 18 lines]
> Here is a pretty thorough description of the process:
> http://www.dmcnews.com/Techsection/r134.html

and of course any rubber bits in the system. A drop in replacement gas
would be an easier way to go.

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