Porsche951redt

Ok so i did a little search around the forums found some information but not too much concerning A/C repair. Looked on Clarks Garage found some usefull stuff but still no definitive answer. Looked in my car for some answers, walked away sweating enought to fill a river and proabably 10lbs lighter. I should charge people money and lend my car out as a sauna ... Basicaly my A/C works but it blows nothing but hot air.

So my question is since i assume our cars are using the old R-12 Freon do i need to make any modifications to any of the system components to run the new R-134A Freon? Also where can i get some R-134A, because last time i checked you had to a be a licenced A/C mechanic to get some....

Porsche-O-Phile

This subject has been beaten to death, but yes you'll need to modify the system for r134a. At a minimum you'll need new fittings; ideally you'd use a different compressor, condensor and evaporator. You can get r134a anywhere without certification. R12 does require a certification (at least in the U.S.) but it's idiotically simple and about 20 bucks to get one. Or you can buy r12 off some dude in Mexico like I do.

Porsche951redt

What happens if i put the R-134A and dont modify anything? How much would all that cost to buy?

MitchB

If the system is OK, why would you convert to inferior R134A? The cost of the conversion far outweighs the extra cost of buying R12...

My .02...

ehall

new compressor...around 500 US. Used...still too much.

Porsche-O-Phile

You'll need to have the remaining r12 completely evacuated along with all the remaining oil. At that point, replace the receiver-drier & associated o-rings and you can convert. Performance will be fine when the engine is up to speed but inferior when at idle since r134a is less effective than r12 at cooling. If you're sitting in a lot of stop-go traffic I'd go with r12 or something like a freeze-12.

ehall

also see the other thread entitled "Ghetto A/c"


Jeff, what's the chem. diff between Freeze 12 and real R12?

pflyers

I had a bad compressor and picked one up off ebay for about $75.

then replaced the o rings where all the hoses connect (pretty obvious where they go) total of about 5 hours including jacking up the car etc...

I ran out of r12 and was sick of the hassel trying to find more so ordered some freeze 12.

It blows cold around town and much colder than freon on the freeway.

been in my car now for quite a while, no problems. from what I understand it's totally compatible with r12 however do your own research.

paul

Porsche-O-Phile

Ask and ye shall receive:

http://www.freeze12.com/pdf/6030.pdf

ehall

NIce MSDS grab. Thanks. R134 and freeze 12 are both composed almost totally of 1,1,1,2 tetrafluoroethane. I have a bottle of R134a in my hand.

Porsche951redt

Yea my A/C runs fine it just blows hot air instead of cold but the compressor and clutch are all in good shape. I was never intent on doing a convertion i just wanted to know what would solve the problem while spending less money. I am in Canada how do i go about obtaining R-12??? Unfortunately i cant go to some dude in Mexico to get it lol.... so any other suggetions?

Zero10

Where are you in canada? I've been helping a friend fix his A/C in Calgary, as well as fixing my own. If you're near-by, I could lend you a hand as well.

Most of the R12 substitutes are essentially propane. It cools insanely well, but has it's down sides. The compressor will cycle more frequently, since the evaporator will keep freezing up, this causes you to get really cold air, then warm air, then really cold air, etc. Also, if you ever develop a leak in the system, you are venting highly explosive propane. This happened during an engine fire in my 86, and nearly blew the hood right off the car. Because of this, I will never use a hydrocarbon refrigerant in my cars again (for more than a week or two to find leaks). IIRC, this includes Duracool, RedTek, and perhaps others.

It would appear Freeze 12 is R134, with an additive to allow it to work with R12 oils, so that it can simply be added to a R12 system, and will work. I suppose, for best functionality, you should evacuate the system first, so there is only one refrigerant in there.

As far as getting R12 in canada, forget about it. The 2 biggest sources of it are China, and Mexico. Rather tough to get it into our country, and paying the rates up here to buy it... well, they're just too high.

So, when you press the button, the compressor kicks on? I am confused why it would not blow cold air, unless either your low pressure switch is bad, or you have compressed air in the system instead of refrigerant. Should nail down why it blows hot before you worry about recharging it. Check the low side pressure, and check out the low pressure switch.
If the system has over 30-40psi (with the A/C off) on the low side, then you have adequate pressure for the compressor to kick on. This means your low pressure switch is probably good, and that you have a different problem. If this is the case, and the compressor is kicking on, then I would have a shop look at it, since you could have a plugged expansion valve, or another serious problem.

If there is no pressure, then change the low pressure switch (I have a new one if you would like it), and try throwing a can of Duracool into it (the cheapest refrigerant I could find), and see how long it will hold a charge. If it holds for a week or two, have it vacuumed and filled, otherwise, fix the leaks, and repeat. It's how I'm pinning down my leaks.

Porsche951redt

Hrm.... well if i knew what the compressor sounded like i might be able to tell you if it starts turnin. Let alone if i knew where the hell the A/C system is located in our cars. I read up a little about how it works on clarks garage but if you show me a part and tell me to indentify it its over... I am in Waterloo ON. and when i turn it on and let it go for a while it will blow semi cold air, i would say when the temp is 100F per say, outside, then the vents blow 90F at the coldest. WHen it starts up it blows 98F. So it is cooling the air a little bit but not alot. I asked my dad he said just put in some new Freon.... i mean after 16 years R-12 has got to loose its properties a little bit.

ehall

the haynes manual isn't great, but you need to get one if you want to keep one of these cars on the road without going broke. At some point you really need to buy the actual manuals, or find a place to downlaod them. This is'nt hard stuff, you just have to get the directions, then follow them.
Now, you need first to determine if your heater door clip is attached. If not, the heater door is open, and will blow HOT air into the car. The tiny little part is under the dash, above your right knee, as the driver. You have to reach up, and behind the bottom of the dash. If it's broken, you'll feel a little 4 inch long metal rod, hanging down freely.
You can also crawl under, and look. I'm a little big for that,so it wasn't fun, but I found it. The part is like 2 bucks. Check there first. It's VERY COMMON!. Then let us know, and we'll get you through the rest. The Haynes man. is less than 20 bucks. Pick one up. BTW, put the car up[ on stands, and it's the other large thing attached to the big belt. It's on the driver side under the engine, connected to the alt by a belt. There's a start.

Porsche951redt

Holy crap.... well that saved me about, well ALOT OF MONEY! Thanks a million that little plastic peice of crap was the problem. I could not find it at first because in the 89 the assembly is hidden behind a shroud but i finaly got it. And yep you called it the little plastic peice that holds the metal peice to the mechanical actuator thing was busted. I was wondering because when i was driving back from my mechanics house on a long trip i hit the accelerator and the all of a sudden my ac began to SPILL hot air into the cabin. Just like that and i guess that is when it broke. I mean the A/C still was not that great to begin with but hey 16 years old what can ya ask for right? If the opportunity comes along though if any one has some R-12 laying around i gladly buy a batch off of you.