Easy A/C question

[granitestategn]

My A/C doesn't blow cold anymore, just barely cool. I have never added freon to my A/C system before and I was given (2) older R-12 refill canisters and single hose/guage fill kit. It's not a full blown set of guages and hoses. How do I add some R-12 to my system? The guage has a green zone on the scale. Which fitting do I add the freon to? This one should be a slam dunk for one of you A/C experts out there. I did a search and just found a bunch of opinions on refridgerants but no procedure. Thanks in advance.

 

[Red Regal T]

Just add a can. If cold and your compressor isn't clicking on and off you done. If compressor is still clicking on and off, it'll take more. Safe to add until the compressor stays engaged. After that, you'd need gauges to see where you are.

 

[granitestategn]

Thanks John.

I did a little pokin' around on the net and found a generic site that went through the procedure on how to top off R-12 systems. I would guess the green zone on the guage is the correct low side pressure for an automotive system. I also understand that the fittings are different size so I can't get hooked up to the wrong side. I'll take it slow and careful and I should be OK. I have three vehicles that are all down on charge. I'll use up the R-12 that I have and may take the other ones in to get them topped off. The other alternative might be Freeze 12.

 

[Rickracer]

I would stay away from Freeze 12

If you read the ingredients, it has some propane in it. Not good. Also, very few will be willing to service your system after adding the Freeze 12 unless they have a dedicated setup for that specific refridgerant.

 

[Gnx6]

I've been using envirosafe R12A for 5 Years in my daily driver, (94 Cavalier) and it works great.

Yes, they all will have some kind of propane or butane, it is needed as a propelant and absorbent for the oil. My Cav had seapage in the Condenser core, add a little stop leak and it's been good for 5 years. The argument about hydrocarbon refrigerants with propane/butane in them will never end. The envirosafe has the least amount of butane in it of all the blends. The propane/butane will disipate so quickly in a crash it is not an issue. Unless you crash into a car on fire (In which case you'll probably be dead anyway) it is fine.

Most of the tests where they show the car expolding with hybrid refrigerants is because they are 90% propane/butane.

Keep in mind with the GN the compressor will cycle on a cool day. Ideally you want the low side to sit around 30 psi. If the gauge drops rapidly and the compressor cycles often put another can into it. If it is a hot day the compressor will run constantly at idle.

You can find envirosafe at www.autorefrigerants.com

Keep in mind, The envirosafe is compatible with an R12 or 134a A/C system but is NOT compatible with R12 or 134a refrigerants. The stuff is harmless to the enviroment so if you need to service the system you can recover it whatever way you want.

I've heard and read some nasty stuff about that freeze 12 crap, I would stay away from it.

 

[granitestategn]

Thanks Scott

Anyone who does a search on refridgerants will find there's no shortage of controversy on what to use and what is dangerous. I'm no expert, but my opinion is that there is probably no "safe" refridgerant. I'm not a tree hugger but I don't dump my oil down the storm sewer either. I find it hard to believe that my contribution to the whole in the ozone layer adds up to didley squat compared to the auto salvage, HVAC and scrap metal dealers. I work for an industrial plant an we get A/C units, fridges, dehumidifiers and old propane tanks "donated" or dumped on our property all the time. The company pays $$$$$ to have that stuff disposed of properly. As far as safety, some "safe" refridgerants convert to phosgene gas when combusted. We have propane fork trucks at work. I walk by them all the time without fear of them exploding. They're not a problem unless you get a big leak. Then it's like everything else, you got a problem and you need to deal with it. At some point I may do a whole conversion. For now I'd just like to get it cold. I'm not gonna lose any sleep over my square foot of the ozone hole.

Wait.....I've got an idea! Let's get a big fan and blow all that bad ground level ozone that we have so much of up to where the hole is. Problem solved! Oh wait....I got a better idea! Let's put big tall exhaust pipes on all our cars so we can put our oxides of nitrogen way up in the sky where they can convert to ozone up next to the hole. I'll call the power company to have them bury all their lines so we don't hit them.

 

[Red Regal T]

Just put the "stuff" you have into the nipple on the drier. That is low side.

 

[Rickracer]

I'm with you Gregg

I never did buy into that ozone hole crap. One volcano spews more chlorine gas into the atmosphere than all the freon ever made. Do you seen the ozone hole getting bigger every time a volcano goes off? I wouldn't worry so much about propane fuel systems either, but it would trouble me to know it was in my a/C system only because they are so prone to leakage, and damage in the event of an accident. Basically for me, it boils down to a question of economics and liabilities. R134A is low cost and the lowest liability.

 

[Gnx6]

One thing to keep in mind. The molecular composition of R134a is much smaller than R12.

For example, you have a car with a slow leak and it takes about 6 months to run dry with R12 refrigerant.

Then take that same car and put 134a into it. The system will be empty in days.

134a does work but in older cars I wouldn't reccomend it. If you have a new compressor and all new seals then go for it. In general, 134a sucks a$$. If you can get r12, use it.

On another note, when 134a is in a system that contains a small amount of moisure it will form an acid that will rot the pipes from the inside out. Not to mention corrode all of your line fittings so they all break when you try to un thread them.

134a was never a solution to the global refrigerant problem, or to better system performance. It is nothing short of a band aid.

R12 is an ozone depleter, R134a is a green house gas. I see way more problems with 134a then I ever did with R12. Cars that used to go 5 to 8 years without needing repairs (LEAKS) are now needing them in less than 3.

 

[granitestategn]

Huh?

OK, last night I hooked up my can of genuine R-12 freon to the low side fitting on the A/C system and the gauge says 75 PSI. I have the engine running, A/C on high, fan on high. Compressor was not running so the lines too and from the compressor were the same temp. Will the low side pressure read that high w/o the compressor running? Does it drop when the compressor turns on? I checked the A/C fuse and it was OK. Should I jumper something out to get the compressor to run or just add more freon? I wonder if my problem is a bad switch? Any suggestions?

 

[salvageV6]

Yes it can read that high when not on.

I would first check the A/C fuse, then the solenoid fuse, then I would check the accumulator switch with the connector OFF it.

Put an OHMMETER on the low ohms scale and look for low ohms short accross the two terminals of that switch.

Should read under 3 ohms.

When my TCC shorted out and blew the solenoid fuse the A/C stopped working in my car. You need the solenoid fuse to run the A/C cutout relay.

 

[granitestategn]

cool

I kinda thought that the pressure might read high w/o the compressor running. I would guess the system pressure equalizes throughout the system. Does the low pressure switch allow the compressor to start and them shut it off once the pressure on the low side drops? Then it cycles all over again? And again? If that's true, the compressor should always be able to start, even if it's low on charge. Am I correct or am I all goofed up?

 

[Rickracer]

The switch on the accumulator is a low pressure switch

It will open at between 10 and 18 psi. It must be closed for the compressor to run. Check both terminals to make sure one has B+ when the A/C is turned on. If one does not, start checking fuses.

 

[granitestategn]

I feel kinda stupid......

Um.......it was a stuck low pressure switch. I jumpered the plug for the low pressure switch and the compressor started. The low side pressure dropped to about 25 PSI and stayed there. Now it blows cold. About 41 deg. F. I didn't add any of my freon so I can save it for later. When I put the plug back on the LP switch the compressor wouldn't run. Tap, tap, tap with a screwdriver handle and VOILA! It works. Thanks for your help guys. At least I know more about A/C than before. If I would have taken it in I'm sure they would have charged me some $$$$$$.

 

[gnsrule]

Yes, they all will have some kind of propane or butane, it is needed as a propelant and absorbent for the oil.

Im hopeing your refering to some of the afterthefact "freon's " out there. The original r-12 is "Dicloraldifloralmethane" if memory serves me. Propane makes for a very good freon, the boiling point is there for makeing cold ****, but i belive its outlawd to be used. I would think all aftermarked freon, ie: freeze 12 etc is safe. Im not a chemist, but why would a refrigerant need a propelant ?? The compresser is the propeling thing.
The oil imo never gets absorbed. Every condenser or evaporator ive ever flushed out had a **** load of yellow ****ty muckey looking stuff in it, presumably oil and dirt. That tells me that it was not absorbed buit rather half ass mixed thru the flowing action of the freon thru the system and when shut off it just settles to the lowest point.
Just my 02

 

[salvageV6]

We had a guy at work, masters degree from MIT in ME.

Used propane in his beemer 320 from about 1980 vintage.

Once he fixed all the leaks in the system it worked fine.

Guy only made about $85K a year.

Got 400K miles on it before he had to do headgaskets.

I think he used less propane than freon but I'm sure he had it calculated down to the 1/4 oz.

He also built a water separator for his air compressor so he could paint body parts on his other car a Citroen.

Took him about 2 months to make it at work and I think they have them for about $15 at Home Depot or Northern.

People are very interesting creatures.

He didn't blow up yet last time I talked to him.