Modern A/C swap from donor?

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Longroof79

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Longroof79

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Oct 14, 2008
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Gainesville, Fl
FYI…It a general consensus that R4 compressors are junk from the factory. Another GM failure. They leak Freon and sling oil everywhere. Look at the bottom of your hood at the compressor location and you’ll see an oil stain. I ran them for years with Oldsmobile engines. It was painfull to replace hood felt, oil and freon every few years. Now I run an LS with a Sanden compressor.
Doug,
Does the Sanden compressor use the same PAG oil as the stock R4 equipped system?
 

L92 OLDS

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Mar 30, 2012
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Doug,
Does the Sanden compressor use the same PAG oil as the stock R4 equipped system?
Since getting sick I haven’t gotten around to replacing the condenser, lines and hooking everything up. Part of the problem has been sourcing a cross flow condenser. I’m tempted to take it somewhere to make it right but I don’t like other people working on my stuff.
Based on the pic below I don’t think the oil is exactly the same.
1629153747103.jpeg
1629153594429.jpeg
 
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ELCAM

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Thanks for that information. It certainly opens up another option. But, is it worth acquiring the tools, and will it be a continued problem with seals going periodically?

I got into A/C work because so many times the "professionals" would fail. Hundreds of dollars and next summer it would blow hot air again. I have fixed things that had been fixed 3-4 times at great expense and had them never have the problem again a lot of these cars went to the salvage yard with other problems or sold and the air still blew cold.

Will it need repaired again, probably, keep in mind the R4 is a poor design but it could last for 10 years with quality parts the proper oil etc. I never use chain store parts, only buy from where real professionals source their parts. Mystery parts from e bay are just gambleing if you value your time you won't use them. If you have to stand behind them same thing. On that seal there is a standard single lip seal but also a dual lip seal price is about double $8 VS $16.

A lot of the tools are fairly inexpensive, the ones in the write up are cheap except for the plate puller and it is not too expensive. The gauges, vacuum pump leak detector and some pullers can be pricey but not terrible. But you might not need all that.

A/C work is right or wrong no middle ground. It needs perfect cleanliness, all procedures followed to the letter. The right oil in the right amount placed in the right places. The exact amount of refrigerant. Using only top quality parts. No corners cut.
 
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ELCAM

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Doug,
Does the Sanden compressor use the same PAG oil as the stock R4 equipped system?

An R4 uses PAG 150 a much higher viscosity oil than the PAG 15 that the Sanden uses.
 
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81cutlass

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R4 in the old days used mineral oil

R134 uses synthetic oils, some synthetics are backwards compatible, but mineral oil is not forward compatible.

If you reuse the stock evaporator and condensor and lines and swap to r134 it's a decent idea to get as much of the old oil out as possible.

The anal AC people will tell you to swap EVERYTHING from R12 to R134 but 99% of the time it's fine. If the old part blows up who cares, you would have replaced it anyways.
 
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Longroof79

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Oct 14, 2008
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An R4 uses PAG 150 a much higher viscosity oil than the PAG 15 that the Sanden uses.
So, if I do decide to go with the Sanden setup, it will certainly entail completely flushing the system.
 

Longroof79

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Oct 14, 2008
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Gainesville, Fl
R4 in the old days used mineral oil

R134 uses synthetic oils, some synthetics are backwards compatible, but mineral oil is not forward compatible.

If you reuse the stock evaporator and condensor and lines and swap to r134 it's a decent idea to get as much of the old oil out as possible.

The anal AC people will tell you to swap EVERYTHING from R12 to R134 but 99% of the time it's fine. If the old part blows up who cares, you would have replaced it anyways.
I figured it would involve having to flush the system entirely. Thanks for your feedback, Jake.
 

ELCAM

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So, if I do decide to go with the Sanden setup, it will certainly entail completely flushing the system.
Yes, you will have to change the receiver drier and flush the rest. that's the beauty of the old system it is easily flushed. Modern condensers often cannot be flushed properly you have to replace them.
 

Longroof79

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Oct 14, 2008
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Yes, you will have to change the receiver drier and flush the rest. that's the beauty of the old system it is easily flushed. Modern condensers often cannot be flushed properly you have to replace them.
Thank you, I appreciate all the useful information. My system currently is still fairly new. Brand new AC Delco compressor, new condenser, evaporator, drier, liquid line and hoses, etc. I'm thinking it might be cost effective to replace the seal in my compressor and try to get a few more years out of it.
All the parts and components were bought on Amazon and Rock Auto.
 
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