Hi everyone,

I’m not an AC techie, nor a chemist or biologist, so I have become completely lost in the various internet sites and conflicting information. All I am trying to do is convert my auto AC from R12 to R134a and would appreciate some advice.

Car is a 93 Corvette and was running R12. The compressor (Denso 10PA20C) developed a front shaft seal leak, so in my infinite (or not) wisdom, I decided to totally rebuild the compressor with new bearings/thrust washers/seals etc. No problem so far, the comp is on the bench in a 100 pieces and thankfully no signs of undue wear or any particle contamination and it should go back together ok.

Now…!!!, not knowing anything about AC, my info comes from the net and here is where I’m stuck/confused.


......what type of oil do I use for this compressor with a R134a retrofit?

I’ve read that it should be PAG46 (Denso’s recommendation for the comp), I’ve also read that it should be a 100 viscosity Ester oil (so that it doesn’t react with any residue oil left in the system), another opinion suggests a PAG ‘d-capped’, what and why the later is I don’t know.

In a fleeting moment where I thought I understood what was needed, I went and bought a liter of ‘Emkarate RL2000’ that the garage salesman waved under my nose. I’m now not sure if this is the correct oil and particularly if it is the right viscosity… the product sheet says ISO68 !?

Another web contradiction I’m coming across is whether it’s a good idea to flush the system or not, if so what with and how?

Any opinions/suggestions please?

Many thanks.

PS: I know I need new R134a compatible seals, gauge/charge adaptors and I’m fitting a new accumulator/drier for good measure. I’ll also have the system recharged at 60-70% of R12 recommendations