It seems to me it wasn’t all that long ago that anything to do with an A/C system was heavily regulated and out of reach for the home shop repairman. I’m not even sure when this changed. It obviously has something to do with the fact that the new “134a” gas is no longer regulated (ie: not thought to cause o-zone depletion), but it also destroys the mystique of A/C units — the very fact that you can repair them yourself.
Christine came home from work Friday complaining that the A/C cut out on the Taurus that morning. Regular readers will remember that we just finished fixing the starter in the Taurus and more than that, it was laid up for nearly a month while we figured that one out… so Christine was rather despondent about it. We’re in the middle of a heat wave here in Southern Ontario and the auto climate system in the Taurus isn’t exactly friendly to use without it’s ability to cool. In fact, the defrost function often gets it very wrong under these conditions as it expects to use the A/C system to dry the air for defrost duty.
I spent some time on the intertubes (of course). The Taurus Car Club of America is a favorite spot. I also accessed my alldatadiy subscription. With the car running I could hear the compressor cutting in and out repeatedly and the air from the vents was “somewhat” colder than the ambient. From this research, I concluded that the car was low but not out of A/C gas.
Enter the Red-Tek A/C recharge kit. The picture to the right is the guage that comes with the kit which includes the guage and two 6 oz cans of 134a with dye. The “dye” allows one to spot leaks and it otherwise apparently harmless. Here in Canada, PartSource and Canadian Tire are both selling the kit for $55 and the refills (if you need more) for $17. They also sell two different leak plugging products (at least one of which was warned against for most applications in the online forums) and an oil boosting product. You can also get the 134a without the dye if you prefer. I’ll add the note here that the Sears Craftsman Red Cabinet was a gift that I really appreciate from my late father-in-law Gary Enright.
The kit is fairly simple to use. You’ll have two connections under the hood the “high side” (on which the connector will not fit) and the “low side.” On the Taurus, the low side is almost hidden near the firewall on the passenger side. The “high side” connector, on the other hand, sticks up conveniently right in front of the coolant reservoir. Connect a can of 134a to the end with the butterfly fitting. With this connected, connect the quick-connect side to your “low side” port.
In my case, at this point (engine, off) there was 30PSI reading on the guage — meaning that the system had not lost all of it’s gas (this is a good thing). The package recommends a starting charge, but in my case, releasing gas from the can immediately shot the pressure up to 40 psi where the target range is apparently 30 to 38 psi. I had Christine start the car and put the A/C on “max” (the next step in the instructions) and the pressure dropped relatively immediately to around 10 psi (and I could hear the compressor cutting out). I opened the can further and the pressure stabilized just above 30 psi until the can was empty. I think you could let the gas rush in faster, but I was being cautious.
The can gets cold as the gas exits and you can tell when the can is empty as it gets warm. In my case, we were at 25 psi (the system was cooling) after the first can, so I elected to add a second can. It seemed to state that you disconnect from the car’s “low port” first before removing the can — I honestly don’t know what sort of check valves the thing has and the directions were light on the topic. For safety, I disconnected from the car, removed the old can, inserted the new and resumed filling. I also tried shutting the car off — but this resulted in the “low side” pressure rising dramatically — over 70 psi and I reasoned that removing the “low side” fitting while the compressor was running (at 20 or 30 psi) was much preferable (less lost gas) than at 70 psi or more with it stopped. There may be a point where this goes back down if you wait long enough, but I did not.
In all, 2 cans (6 oz each) brought the low side pressure back to 34 psi — right in the middle of “good” and the cool air was flowing. AllData says that my capacity is 34 oz, so it would seem that we possibly lost 1/3 of the total gas. If this is “since we bought the car” … it’s definitely acceptable. If this is recently, then there will likely be another post on this subject.