rich30769

OK, here's the scenerio. Yesterday approx. 92 degrees in NYC. I decided to convert my ac to r134a. When I hooked up the manifold gauges to remove the old freon, nothing registered on the gauges. OK. Replaced the fittings for the high and low lines used the cheap hose that the kit came with the kit to refill the freon, first can went in with no problem(these cans are 12oz cans, each one contains 3oz. of oil, so it states)second can of freon all over the place, the cheap hose was stripped. Retrieve another hose, got the 3rd can in no problem. Turned on the ac and all is fine until I give it gas. The AC cut off and wouldn't come back on. Today got in the car approx. 98 degrees in NYC, AC came on, gave it gas, no more ac. Compressor shut off once I gave it gas. It seems that when I start the car the compressor comes on but as soon as I give it gas it shuts off and doesn't come back on..

PS: The car sat over the winter as I did the valve guides and seals so no I didn't have a chance to run the AC over the winter..

Does anyone have any answers for me??

TIA

Hal H

R134a runs at a higher pressure than R-12 systems do...

I remember reading this on various websites that its not a good idea to simply swap R-12 out like you described.

The old R-12 must be completely evacuated as well as the old lubricant - R134a requires an entirely different type of oil.

What may be happening is that when the rpm's increase, the head pressure (high side) may exceed operating limits and the system shuts down to protect the compressor from damage.

One of the other substitutes that I've read about (and requires much less modification) is to use FR-12 (blend of different refrigerants)

The FR-12 seems to perform better than 134a (more cooling) with lower operating pressures much more closer to the old R-12. And you don't have to modify the condensor to make it work for FR-12.

I'm not an A/C tech, but this is the research I've found in looking around on this topic in the past...

rich30769

Hal,
Thanks for the response. The damn thing started working and it's still working. Don't have a clue as to why all of a sudden but it's on. Where can the FR-12 be purchased or is it one of those, you must be a mechanic or have your on shop type of deals?

I'm sure your off to enjoy your 4th. Be safe and have a good one.

Hal H

http://www.refimax.com/products/fr12_conversion.htm

there's literature in there as well, so this should help.