LarryD

Ok, so here is what I did and the results:

Initial Problem: Warm Air and Compressor Cycling on/off in 3 seconds

Verified the relay and pressure switches were working ok.
Bought an R12/R134a Manifold Gauge set and verified pressure low.
Bought a Venturi Vacuum (already had an air compressor).
Bought the GM High Side fitting adaptor for the manifold set.
Got my EPA 609 certification.
Bought 3 cans of AutoFrost 406a on EBay.

Had the R12 recovered at a shop so I could work on it after that.
Removed the Orifice Tube and Accumulator.
Blew out all the lines with compressed air.
Replaced the Orifice Tube with a new stock replacement.
Replaced the Accumulator with a new stock replacement.
Added 2.5 ounces of Ester Oil to the new Accumulator.
Added about 1 ounce of ester oil to the Compressor low pressure line.
Pulled a Vacuum for about 40 minutes (couldn't quite get a hard vacuum but close)

A 92 Camaro RS V6 takes 2.25lbs of R12 so that equates to exactly 3 of the 9.6 ounce cans of AutoFrost 406a.

Added 2 cans of AutoFrost 406a to the low side fitting.
Started it up and let the compressor run a couple of minutes.
Added 1 more can of AutoFrost 406a to the low side fitting and got good steady pressures (no cycling).
Verified the low and high side pressures.

Took about 2 hours to do all the work (not including getting the R12 recovered at a shop).. Been running it off and on for about 3 weeks now..........

It Works Great!!!!!!!!! 78 to 80 degrees outside ambient temperature. Inside vent temperature at idle is 38 degrees, vent temperature at 35mph is 35 to 36 degrees, and vent temperature at 65mph is 33 to 34 degrees...

Reid Fleming

iTrader: (2)

Bravo!

I found that it will still do those low duct temps even when the outside temperature is in the 90's.
----------
As much as I like playing around with the SuperRam and the new exhaust. I gotta admit, having air conditioning that works this cold just makes driving the car a whole new experience. Particularly on those heatwave days. It's not just cooling, it's actually COLD! Very soothing.

186irocz

someone knows how to do a/c right! congrats dont u love having an old car with colder a/c then a new 1.

LarryD

Thanks... It is great to have cold air again particularly since my car is black with the black interior and even though I am in the Seattle area, we are getting some days in the 80's now... Just a note on the availability of AutoFrost 406a... The Frosty Freeze guy on EBay doesn't have it anymore but it is available through Refrigerant Sales. They are not going to carry the 9.6 ounce cans once they run out but they still plan to carry the 30lb bottles. A case of 12 cans runs about $95....

Reid Fleming

iTrader: (2)

Why did you use ester oil?

My Harrison compressor says 6 oz of oil.

LarryD

Ester oil was available at the time I was picking it up and mineral oil was not. Based on my reading Ester should be compatible with R12 and R134a. I didn't find any real information on oil for blends. Right or wrong, I may find out after a few months (backup compressor is ready to go though). I did not drain the compressor (only blew out all the lines with them disconnected) and only needed to add a little in case of leaks with age and due to the replacement of the accumulator so that is why I used only a few ounces. It was a somewhat educated guess being conservative so as to not add too much....

TexasSilhouette

iTrader: (4)

I've had an R-12 91 Bird and a different one converted to 134A. I converted the 134a one to Autofrost. Rough conversion once the system is tainted with 134a as all the PAG oil must go. Worth the effort as the Autofrost cools MUCH better than the 134A.