What are the differences in the Denso A/C compressor for the r12 versions and r134a in later model cars? The general model of the compressor is the 10PA20C, but i'm curious if there is any real difference (besides what type of oil they come filled with) between the two models.
thanks,
Will

 

I was also wondering about this - i.e., when it's time to replace an R-12 compressor in a pre-1994 car, is it prudent to choose the R-134a replacement compressor from the 94 and later models? Has anyone done this and were there any problems with fitment?

 

The top of the R12 compressors have a different "hat" to where the R134a lines won't fit. You can always swap the hat.

I cleansed and flushed a R12 compressor and tried to use it in the R134a system with the right oil and amount. It lasted about a mile before it started whining.

 

I ended up calling Denso about this matter. The tech recommended the 94 and later compressor and receiver/dryer. I ended up ordering the 471-1215 compressor and will return the r12 model. Since I have a sinus infection I can't tell you the results now, but on the back of the compressors the stated design pressures are significantly different. Also, the receiver/dryer look identical, but I held both at the same time (both Denso) and the r12 version was heavier so there is some sort of internal difference. My OE compressor always whined on r134a (never experienced r12 since car was bought this way). Last year i put in a rebuilt compressor off ebay (golds auto or something of that nature, it was cheap, but they had good reviews) and the compressor did not whine at first, but shortly did. It blew very cold, so I don't know if it had to do with the rebuild or the fact that it was an r12 compressor. I drained it of the oil it came with and refilled with ester to the recommended level. The sound with both compressors was like a deep grind, but they always continued to work, no failure.

 

Is it almost like a flutter noise? I have a 93 I guess it was converted by previous owner it was fine for about 3 years and started making like fluttering, deep grinding noise for over a year and never quit on me

 

I remember seeing something about the oils turning into acid on conversions after the fact. You have to use a specific oil and it makes sense that it messes it up.

Mine is still working although its not as cold.