R4 to Sanden AC conversion 91 Suburban

blue_tractor_man · May 11, 2018

I have a 91 Suburban and it goes through the R4 (pancake) compressors every couple of years. I use the real Delco compressors, but they still gey noisy and go bad. Should I try to switch it over to a Sanden style compressor? I think there are kits that will do that.

Sprint 6 · May 11, 2018

Something is not being done right when your A/C is serviced. Nothing wrong with an R4 compressor, the bugs were worked out by '91. My '94 still has its original R4 at 190K miles. Leaks a bit, but top off every year or so. I would bet the system needs flushed properly, the orifice and accumulator replaced, and filled with the proper amount and type of refrigerant oil.

gab · May 11, 2018

I had a radial 4 compressor in my 90 GMC, sold it with 286,000 on it, same compressor on it. Those all made a rattling noise. You got something else wrong like a plugged orifice or accumulator.

Hobo,NC · May 11, 2018

Sanden compressors are hard to beat. No love lost here for a R4 they are junk, the good I have made a many a dollar replacing them

...

I have converted a many 96 and up to a Sanden never had a issue are a leaker like all GM's do from the factory...

Steve@Advance · May 11, 2018

Their website says they can be retrofitted, but I couldn't find the application. Probably a call to the factory or a distributor could get the information.

But, a big concern would be system contamination. When a compressor fails it sheds metal into the system. Each consecutive failure only makes it worse.

The condenser is the hardest part to clean. Replacing it would be the best solution. The lines and evaporator can be flushed. The receiver and orifice tube should always be replaced.

The retro kit should come with a new orifice and oil recommendations.

guido · May 11, 2018

Hello Blue_tractor_man,

They were Not the best units, but I think 2 years after 2 years is a proper service issue,

Guido.

Bob · May 11, 2018

Tell us the "rest of the story"!

The vehicle left the factory with R12 refrigerant and mineral oil in the AC system.

Gonna GUESS it's been retrofitted to R134A.

Are you running POE oil or PAG oil?

Either way, I'm gonna speculate you are losing the oil through a leak in the AC system, and the R-4's are beating themselves to death without lube.

They are a decent unit, used as designed, with R12 and mineral oil.

shinnery · May 12, 2018

I have a 83 Mercedes Benz 300TD that has a Harrison Compressor on it. I would love to be able to afford a Sanden conversion kit. maybe this summer.

blue_tractor_man · May 12, 2018

I guess I should have noted that it was 12 converted to 134. I have it repaired at a reputable shop that has all of the correct equipment. Evacuated and new drier every replacement. He told me that he puts in extra PAG oil or something because it is an R4. Thanks.

R4 to Sanden AC conversion 91 Suburban

blue_tractor_man

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Sprint 6

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gab

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Hobo,NC

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Steve@Advance

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guido

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Bob

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shinnery

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blue_tractor_man

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