I am having a problem with my AC not blowing cold. Everything seems to be working properly, the clutch is engaging and the fan is blowing hard. Not sure what the problem could be but thought I may need to check pressures. So..... the question is what should the pressures be and how do I check them?

 

Because I've answered this so many times.....

http://blarg.introspect.net/?p=7

Please feel free to ask any questions if you need more specifics.

 

35-40psi low
150-170psi hi

Get a Harbor Freight AC test guage

Early 85.1 944s need a 90 degree fitting under the compressor to hook up a guage. A 1 inch shorter belt is also required.

If you have an oil patch under your compressor, usually the front seal is bad. Compressor must be resealed.

GL
John

 

Nicely done!
Bookmarked.
John

 

Thanks so much, I have a r12 (freeze 12) system, is this going to be the same process?

 

Yes, I noted in there where it is different. And as John_AZ mentioned, your low side port will be actually on the compressor, so you'll need to crawl under there to hook up (and you definitely need the 90 degree adapter for clearance).

Other than that, and the fact that you need to screw the connectors on rather than being quick disconnect, and the pressure differences mentioned here and on my posting (honestly, they're so close to R134a it won't make a difference if your main concern right now is seeing if it's doing anything at all) it's the same procedure. For any car.

The only issue with Freeze-12 is you can't reasonably top it off. It leaks different portions of its gas blend at different rates. If you find that it is so low that you don't even have liquid refrigerant in there and want to stick with Freeze-12, you'll be fine to recharge it. There would be so little left in the system at that point that vacing it wouldn't be necessary in my opinion. If there's a decent amount left (let's say you're getting up to 140 or so on the high side) it probably needs to be recovered/vaced and recharged. But it you're even getting to 140 it would be putting out some amount of cold air for you, so it's probably much lower than that.

 

adding,
If you get to a point where you need to take it to a shop....most shops will not work on your AC system with Freeze-12, it contaminates their equipment. They will check your freon with an electronic sniffer.

Chain and private AC shops are required by the EPA to recover freon.

John

 

Okay, thanks for the response. I actually put the freeze 12 into the system throught the high side port, is this possible. I did not realize the low side port was on the compressor. This could be the reason my AC is not getting cold. I feel pretty stupid. COMMENTS?

 

EVERYONE, including private individuals, are required to recover (or at least not vent) ALL REFRIGERANTS, not just freon (R-12).

It's possible to do, but dangerous and unlikely you'll get much in. I assume you did this with the car running and the AC on.

It's dangerous because in a functioning system, the high side pressure can be around 200 PSI. That is much higher than the pressure the can is supposed to take, so it can burst. They do have a safety on them on the bottom (typically) so it will blow out "nicely" rather than becoming shrapnel, but I still wouldn't want to be around one.

It's unlikely to charge much for the same reason. The static pressure of Freeze-12 in the can is going to be about 80 PSI (depending on temperature) meaning the most you'll get in on the high side is 80 PSI. That's not enough to make it cool at all.

So if this is how you started out, and you just want to give it a go charging with Freeze-12, get yourself the 90 degree adapter and charge it from the low port. If all else is fine, it will just work. Hopefully it will be that easy for you.

If not, it's time for a manifold gauge set so we can get some numbers and be able to diagnose what's going on.

 

DarylJ,

Have you looked at the freon once R134a is eliminated?
Dupont Opteon

http://www2.dupont.com/Refrigerants/...e20101014.html

http://www.popularmechanics.com/cars...h_buzz&mag=pop

Prices are unavailable---some say over $100 a pound...

John

 

Yes, I've been reading about that on and off. It's troubling, to say the least. I've been stockpiling R-12 when I can get it cheap (if you keep up with it, you can grab it for $30 a can on eBay/Craigslist) and plan to do the same with R134a (but I'll probably just buy a couple of bulk cylinders of that). I do a lot of fix and flips, and there is no doubt that you have to have the AC working if you want to get a fair price for what you're selling. This will just make it more expensive.

 

I just went back to look at some more 1234yf articles. Since it will get phased in in Europe first, maybe we have a chance at not taking the initial pricing hit.

The other intersting thing is that its not an Azeotrope (same as R-12 and R-134a) and it's boiling point is .8 of a degree different than R-12 (R-134a is like 5 degrees different) and the vapor pressure is similar. I wonder if it wouldn't actually be a better substitute for R-12 than R-134a or Freeze-12 type blends?

I'll need more specs on it to make a better guess, but that at least has me hopeful.

It seems that it holds temperature better when circulated, which is a big deal for keeping up with the fake-green-consumer market of hybrids (you can keep circulating it at a stop when the gas motor and AC compressor aren't running and it will stay cold for a bit).

 

Comments? No, The can could have exploded in your hand.

If you get the 90 degree adapter, remove the valve from the original before you put the 90 degree adapter on.

Here is the NAPA 1" shorter belt #.
NAPA and buy belt# 25-050390

GL
John

 

Daryl,

I have to read more as well.

I read in one article that the pipes have to be cleaned, really cleaned. This will add to the shop fees.

John

 

I've read it's a "drop-in" replacement for R134a, but that might not mean what I think it means, because that was from the perspective of auto manufacturers. So if it's not compatible with PAG or POE oil, yeah....that's gonna suck. On the bright side, it will be worth buying a better flush system as I'm sure to get a lot of work with it.