I am the stupid homeowner that added R134a.

15 years ago I was a certified Automotive and Diesel Mechanic with additional certification in A/C and Electrical repair. I broke my back in 1995 and forced career change, so no longer certified.

I have 20 year old 2 1/2 ton spit system in my home (Bryant). The system has never given me a bit of problem other than needing a little added refrigerant every 5 years or so.

Last year I put my gauges on and saw that it was time for more refrigerant. I had used up all my R22 on previous service.

Since I am no longer certified, I could not buy any R22 or so I assumed. I did not even think is was available any more (I had confused rumors I heard of R22 Equipment Ban with R22 Ban). So the only thing at hand was R134A and the can said it was compatible with all R12 and R22 systems. (12oz automotive cans, some with POE oil included) I added I think 2or3 12oz cans with or without oil. I am not sure how many cans had oil, but those that did I believe are 10oz of R134A and 2 or 3oz POE oil. All I could find on a Sunday when I had time to work on my system. The system did not get as cold as I thought it should, but I lived with it for remainder of 2009 season.

This year when I tried system for first time I was getting about 65F air out of vents. I again added 2 12oz cans of automotive R134A (no oil). Did not change temp by more than a couple of degrees. A-coil was only getting cold about the bottom 5 inches. Acted as though still low on Refrigerant.

Then I did what I should have done last year, I researched differences in refrigerants and found.
1. R134A only produces about 65% of cooling compared to R22
2. POE oil and MO do not mix
3. R22 is still readily available.

I am not sure how much, but I have to assume that I added 3-6oz of POE oil to my system as many of the automotive cans include this by default. I can not afford to replace entire A/C system at this time and pressures are still good and compressor sounds good. I have evacuated system to 25" vacuum for 6 hours and have ordered R22 to refill system that I should have delivered some time today.

So my question: Everyone talks about how detrimental MO is to R134A and POE system. But what can I expect from POE contamination of my refilled R22 MO system?

my system is:
Year 1989:
I Live in SE Michigan, USA
bryant model 591A030 Condensing Unit
bryant model 507J 030 A-Coil
15ft - 18ft 3/4" Vapor Tube & 3/8" Liquid Tube

Thanks in advance for any advice you may have,
Sincerely, Fred