Heya folks. I have a 92 bonnie se with a 3.8 and an original r12 ac setup. I bought an r134a conversion kit at an auto parts store after checking to see if my unit was still pressurized (which it was but just a small hiss).
I dont know if that means anything and honestly, I have not a clue about ac systems. I read that my ac origninally took 2.87 pounds of r12. I put in a 14 oz bottle of the 134a and still no cold air and the compressor is not running. I guess my question would be, how much do I have to put in so it activates the pressure switch in the compressor? I am guessing if the setup was almost empty, which was my imprssion, than 14oz was not enough. Should I try another pound of 134a to see what happens or maybe just wave the white flag on this car because I dont want to spend a lot changing parts.

BTW, the system did work 3 years ago when I picked the car up and then suddenly stopped.

THANKS!

From what I understand each 14 oz can comes with some kind of treated lubricant right inside. Thanks for the reply. When you say I need 2.4lbs 134a, are you meaning in equivalance to the r-12 or just to work the pressure switch?

THANKS!

If it hasn't run in that length of time and there was no freon in it, you have a leak. I would put in some uv dye and look for the leak, before you waste any more money. Once the leak has been found and repaired, i would run a vacuum pump on it to get rid of any condensation in the system, then do your recharge, don't forget when recharging dont allow any air in the system in between cans, purge the can first.

I would make sure that the compresser even turns on. Jump the low pressure switch on the Receiver drier, if the compresser turns on and doesn't make any abnormal noise put in another can. My Alldata show'* that our cars, i have the same car, takes 2.4 LBS of R12. That is ( 3 ) 12 oz cans of R134a.



Good luck,
Sellncars

Ditto on the leak fix and the vacuum pump. Even if you had no leak, you cannot just take a depressurized system and put cans of R134a into it without running a vacuum pump on it. Well okay, clearly you *can* but you should not, unless you just enjoy wasting your time. The vacuum pump part is not optional, if you want your system to work.

When changing the refrigerant type, you only charge about 85% R-134a based on the maximum charge of the R-12 it is replacing. Like jr's3800 said, if the system called for 2.87 pounds of R-12, you would charge about 2.4 pounds of R-134a into an empty system. If the maximum charge of R-12 was 2.4 pounds, you would only charge 2.0 pounds of R-134a. This is because R-134a runs at higher pressures than R-12.

In my experience, the pressure developed from charging one 12-oz can into an empty system is usually enough to trip the low pressure switch and get the compressor going.

Again, thank you for the replies. I did put in one more 14oz can today, probably because the temp is near 100 and the reward of being cool in the heat was worth the 20.00 risk spent on it.
That makes 28oz and the compressor is not running so I am raising the white flag. Would have been nice but really only needed maybe 2-3 weeks out of the year and I don't want to spend any more on it. The car has 147k on it and runs great.

Just as an aside, I just sold a 92 town car with a 4.6l and can't get over how much more economical the 3.8 in the bonneville is AND how much more get up and go the snotty little motor has. It would have toasted my Town Car off the line and mid range anyway. Great cars.