91 silverado AC parts required for R134a

jwc55 said:

Hello All
I am replacing every last part of the AC system and want to change from R12 to R134a ( or its equivalent). The evaporator has been replaced (stock 91 replacement part) . I'm planning on using a new (95 model) compressor - R134a version, and stock '91 condensor, all lines, and accumulator/drier. Will the stock '91 components be compatible with R134a or is there some design differences between the R12 components and the R134a components. What pressure switches and orifice tube shoul i use, or does it matter?
Thanks
Jim

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GoToGuy said:

All the stock components, new staring from zero. Are compatible with R134. The easiest procedure is to follow the steps in the the factory OE service manual. If your new compressor has overpressure shutoff switch provision, order of new one.
Then the rest is will you be doing the 134 service or a shop ?

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GoToGuy said:

Nope, 95 was first year 134 was installed at factory.
Good he'll be on top of it.

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HotrodZ06 said:

As far as I understand the biggest concern is making sure you use compatible a/c oil. R134a takes PAG46

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PlayingWithTBI said:

Yes, PAG46 - 150, you'll need to flush the entire system to get rid of the mineral oil used in an R12 system - or use an Ester Oil, which is compatible with both.

Another thing, does your panel have a "Max" or "Recirc" button? If so you should have a 2-wire High Pressure Switch on the back of the compressor. If it doesn't, you'll need to replace it with a 2-wire one and hook it up in series with your Low Pressure Cycling switch.

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