Hey All,
New member here. Picked up an 89 S10 blazer a couple of years ago. Moved to HI so I need to finally do the AC conversion. I'll be replacing the lines, pressure connections, dryer, gaskets, and orifice tube. Plan on keeping the original compressor and condenser. Looking for feedback if should just go ahead and replace the condenser. Also looking for feedback on volumes of R134 and esther oil.

She is a 4.3, 4x4.

 

At least for my vintage Blazer (1999), I learned that the condensers have really small passages that are nearly impossible to flush unlime evaporators which can be flushed.

I cannot help with the R12 to R134 switch. You might call an AC shop to find out.

 

I have a classic Ford with a York compressor and my mechanic vacuumed out the R-12 and put in the R-134a and some oil and put an adapter on the low side so I could refill it when needed. That was almost 2 years ago and it has been plenty cold for me.

 

The proper amount of R134a to replace R12:

https://www.electronicshub.org/r-12-...R134a%20charge.

The biggest issue is the oil. R12 used mineral oil and most new R134A installs use PAG. The problem is that mineral oil does not work with R134A and PAG and MO are not compatible and make a gooey mess. POE/ester oil was created to facilitate these retrofits because it works with R134a and will mix OK with residual mineral oil. Its impossible to get all of the mineral oil out of the system and there are arguments on the interebs for days about how much mineral oil can be left in the system during the conversion, especially if PAG oil is used. You can unbolt the compressor and pour that oil out (measure all oil from all components), replace the accumulator/dryer and orifice tube, flush the lines, flush the evap if you like but as Christine said the condensor is hard to flush. You have to replace the oil that you remove (measure if poured out, a chart if flushed). POE/ester is safer, PAG is supposed to work with around 5 - 10 of the mineral oil left in the system. There are arguments for days about how "all I did was put in R134a and it worked fine". I think that we don't get the 12mo+ update with the orifice plugged with green snot and the failed compressor.

George

 

Thank you for that informative reply!! I have a '94 square body s10 blazer that has the r134a adapters on it.. but I know nothing about if/how/when it was converted.
it had ZERO refrigerant in it.. yet has been holding a vacuum for hours.. .so I guess i'll find out what happens when I shoot 32oz of R134a into it (it calls for 2.5lbs of r12)