View Full Version : Auto A/C Recharging Kits

Steve Carbone
07-06-2006, 10:45 AM
Has anyone tried those air conditioner recharge kits they sell at auto parts stores for $40. I think the kit I saw was made by Interdynamics and included everything to convert my R-12 system over to a R134a system without changing any system conponents. Sounds too good to be true. Do these things really work or are they a scam? Stephen.

Jerry Clark
07-06-2006, 11:17 AM
Yes they work-- But--:cool: Depending what model you are converting you should change the O rings at the fittings-- (the new type seal better than the black ones) Also replace the dryer and clean or replace orfice. Drain as much old oil as you can from the compressor, condenser and evaporator and replace with compatible R134 oil-- then evacuate the system for at least 1/2 hour with a vacuum pump. Then you can add the R134 freon (about 80% of the amount listed for R12). If you just dump the R134 freon in without doing the items listed, it will work but not very well. :D

Rob Russell
07-06-2006, 12:17 PM
If you're changing the system over, you really should take it to a place that evacuates and captures all the freon. This is one of those things where little bits really do add up to something important.

Steve Carbone
07-06-2006, 12:31 PM
The car I want to recharge is a 1990 Toyota Camry and the R12 that was in the system has long since leaked out. The pressure gauge I hooked up is showing zero on the high and low sides. You mention draining the old oil out of the system. Is the old oil the R12 that has leaked out or is there something else in the system I have to contend with?

Joe Pelonio
07-06-2006, 12:43 PM
The "old oil" was in with the freon. Those kits are supposed to be compatible and provide the lubrication with the new refrigerant.
Be careful though, as the R134a as cautioned on the can can
be deadly when inhaled, though it doesn't deplete the ozone layer
it's still nasty to humans.

Chuck Wintle
07-06-2006, 1:34 PM
According to a refrigeration person I have talked to there is a direct replacement for R12 called r142B. He claims its does not require any conversion from one to the other.

Jason Roehl
07-06-2006, 8:10 PM
If your old refrigerant has leaked out and you want A/C back, take it to someone who knows what they are doing. Especially since you stated it has been a while since the refrigerant has leaked out. If you want the new stuff to stay in, you have to fix the leak. Time does not fix leaks, instead, on cars, it tends to make them quite a bit worse. My truck's A/C (a '93, the year before everything went to R134a by law), just leaked out this spring. The shop told me they had to convert it before they could even begin to do anything, as they no longer stocked R12 or could get it, and the mechanic didn't even have his R12 gauges at the shop anymore. In the conversion process, they found and fixed the leak (an o-ring on the pressure switch, I think it was), and I was out the door for actually a few dollars less than they originally told me the conversion alone would be. It was still about $375, though, not great, but after a long, hot day painting on a ladder, it's well worth it.

Steve Gray
07-06-2006, 8:47 PM
Your idea of putting 134 into an old 12 system is not a bad one, BUT there are a couple of things that make me worry you will lose your $40.00.
If your gauges show "0" pressure that means that more than likely there was a "large" leak when the system failed in the past. In my experience, o-rings will definitly start to leak over time, but they usually find a pressure that they are "happy" with and reseal themselves with some pressure still in the system. Also if the gauges show "0", and there really was a larger leak, there could be air inside the system. An ac unit will not work well at all if there is air in the system.
Maybe this plan of attack would be helpfull.
Look for any greasy fittings at any connections in the system. Oily fittings will show where the R12 & oil was leaking out in the past. Be sure to look at the connections on the compressor and around the the front clutch on the compressor. Also make sure to look at the evaporator / condensor connections. Look under the front of the car for possible road damage around the bottom radiator area.
IF the system has been empty a long time this might be a moot point, as the leaking oil would eventually be washed off over time, but it is a place to start.
IF everything seems up to par, pull a vacuum on the system. The system should be able to hold at least 20" inches of vacuum for 1/2 hour (24" is really better).
If it all holds then, put in the 134 and enjoy! Most of the kits have an oil charge of about 4 ounces plus the 134. The Pac (134) oil and the 12 oil will not mix but the 134 will carry the pac oil with it through the system, and it will work fine, even with some 12 oil still there.

If you find obvious problems, I would think that replacing a dryer or hoses and o-rings is well within the capability of a woodworker. The new o-rings that we use are blue instead of black. There are 2 important things to remember: 1st, if the compressor is bad make sure you flush the system and not put a new compressor, dryer and orifice tube on a system where the WILL BE contaminants still the the hoses. You will have already way too much money invested to take that chance.
2nd: the only thing that you might not be able to do is to pull the vacuum on the system. You must have the pump designed for this job. Other than that, everything is straight forward, and will just require metric tools and a long needle nose or special orifice tube remover tool.
Hope this might help:)

Steve Carbone
07-07-2006, 2:17 AM
Thanks for the information guys.

John Mihich
07-07-2006, 3:06 AM
I just did this to a 92 Toy and found a leak in one of the connections to the compressor. In hind site I should have just replaced all the o-rings before filling. They are easy to replace and cheap. The retro kit is very easy to use and the directions were clear (this was my 3 or 4 car I've did this with).

Al Willits
07-07-2006, 11:36 AM
Does this unit have the low pressure switch so that when the pressure gets so low it won't let the compressor run?
If not and this thing has been run in a vacuum, you really need someone else to look at this, non condensibles in the system will destroy it (moisture)
Also there used to be a direct replacement for R-12 and you just added it to the system, not sure if its advailible anymore though.

You may want to have a leak check done before you get to involved, that shouldn't cost to much.


Steve Carbone
07-08-2006, 7:47 PM
I'm not sure if it has a low pressure switch but my compressor is not running. I was hoping that the low pressure was the reason. But as some of the others have stated, there has to be a leak somewhwere or the R12 would still be in the system. I guess I'll have my mechanic check it out. Thanks everyone. Stephen.