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.
Red Tek A/C Recharge Kit Guage
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.
You might now volunteer to test the other family A/C systems. Especially Rebecca’s, which is not working, if I remember correctly. Ours gets cold just fine, but the compressor cuts in and out frequently — not sure if that is something we can fix.
The unit doesn’t so much “test” as fill. In Rebecca’s case, I already looked at her problem. Her compressor is seized. When I was going to borrow her car (the day before you helped with the starters), when I got into it and started it, it was making strange noises — basically the belt was stalling on the compressor wheel every time the clutch engaged). Since her system has been empty for so long (obviously) it would at least require repair and then evacuation. Now… I’ve read someone say they made an evaluator using and old fridge compressor, I don’t know if we’re up for that. The downside of not making an evacuator is that acid develops in the system and quickly destroys it. So Rebecca’s repair is at least requiring a new compressor — and whatever pipe work that requires (I haven’t fully read up on how those fittings work, but they are high pressure — 50 to 100 psi easily), evacuation and then charging … of which we know about charging. I had already told Rebecca that fixing her compressor might require a professional. I also told her that it was vital that she not turn on her A/C … since breaking the belt or the A/C pulley would mandate replacing the compressor — and that might not be convenient.
Your case, however, is probably largely like mine. Low gas pressure causes frequent cycling of the compressor (there is a low pressure cutoff switch on the low side line). Ironically, it probably runs fine-ish in hot weather and does the rapid cut out as it gets colder. Anyways… you’d need to stop by partsource and pick up the red tek can ($16.99) and then be in the same place as my guage and hose. One can is probably enough if you’re still cooling.
I should try that, because my a/c has been short-cycling almost since we bought the car. But even on a day when the outside temperature read *40 degrees* (and I could believe it) the air coming from the vents was acceptably cool. But at least for this season I haven’t been able to produce the ice-cream-headache temperature.
Can you look up in your alldatadiy about master cylinder in the Sube? Mine (at least I think it’s the M/C) is behaving badly — especially in near-panic stops (which happen often enough on the 401).
What is the symptom?
Really soft braking on heavy pressure. Inability to lock the wheels, even on a wet road. Guy at the shop recommends a complete brake-fluid flush, which we can do when we do the rear brakes.
Yeah… that might be air or contamination in the system — I’m not sure it would be something wrong with the master cylinder, though. Air and Water are the most likely culprits — or by recommending a flush, that’s what the mechanic is saying. Since the master cylinder is just a piston, I imagine it’s failure modes are rather simple … like leaking. This could be, though, something to do with the brake booster or somesuch. It may be possible that without boost you can’t develop the required pressure to lock things up.
Red-Tek A/C recharge kit!!!!! Did you know that this product is nothing but propane? How nice to be creating a bomb with your a/c system. Propane can act as a very good replacement refrigerant, however that said, it is very flammable. Try correcting your problem with the correct replacement refrigerant that is non-flammable.
You’re the first (seriously) to post that. But being concerned, I did some research. And note that I’m not an internet newbie… I pushed fairly deep. If you have some good articles you’d like me to read, I’d appreciate the post.
Most of what I’ve read so far acknowledges that R12a is flammable, but less-so than (say) a ruptured fuel line. Gasoline has an incredibly low flashpoint and will ignite on your exhaust manifolds. R12a has a flashpoint (at ideal mixture) of about 1584 (from memory). A diesel truck with a stonking 2+ atmosphere boost pulling up a hill at WOT (Wide open throttle) might get it’s exhaust manifold to 1584, but that kind of temperature will quickly destroy your catalytic converter … so you can almost guarantee that you won’t find that temperature in the engine.
In terms of flammability, several posts point out that in a severe leak, the compressor oil is more flammable than the gas. Note that the oil is the same for both R12a and R134a.
I’ve been known to say that if all vehicles were diesel and someone came up with gasoline, there is absolutely no way it would be approved for sale today. Gasoline is amazingly dangerous. Your vehicle is carrying around 30 to 50 kq of gasoline when full. With Red-Tek, we’re talking about 200 to 500 grams of a gas that’s rather hard to light. I’m not saying that you can’t hurt yourself, I’m just saying that gasoline cars are fairly dangerous and prone to engine fires and explosions all by themselves.
I also came across several articles stating that R12a was in use around the world (more so in other countries than Canada and the US) and that nobody could come up with an incident of it injuring someone save a “professor” who emptied a can into the interior of a vehicle and lit a match (not exceedingly bright).