Air Conditioning Issues

Aufgeladen944 · 05-09-2007, 07:50 PM

Yes, I know, the windows do roll down and the roof can come off.

But having a black car with black leather means the interior gets very, very hot, and I enjoy having air conditioning. Mine's not working. It wasn't working when I got the car.

It's low on charge, and it did have the old Freon stuff in it. So I replaced the type of charge, and I tried putting in the R-134. I may have messed that up, but that's not the main problem.

My compressor isn't turning on. How do I see if it's completely busted? I was told by my mechanic that I can't really do anything until I have it charged (they want $200). I'm not willing to pay $200 to find out I need a compressor for $600, and then have to pay labor and another charge of the R-134, too.

Assuming I get the R-134 in there with the help of some of my grease monkey friends, what's the next step to see if the compressor is working. Is there a trip switch I gotta hit to make it turn on after it's been low on charge?

Thanks for any help.

Eldorado · 05-09-2007, 08:52 PM

you do realize that you cant just dump 134 into it without prepping it first, right?

Aufgeladen944 · 05-09-2007, 09:18 PM

Yeah, but I don't think the recharger fits the regular ports. You need to buy the adapter to dump in the R-134.

Either way, my compressor isn't turning on when I hit the A/C button.

Aufgeladen944 · 05-09-2007, 09:26 PM

By the way, if the car needs a new compressor or whatever I'm just gonna take it all out lol.

Eldorado · 05-09-2007, 10:07 PM

not just the valves - you need to flush out the old and use a new oil in your ac system to run the 134.
and freon doesn't just disappear, so you've gotta plug whatever leaks you've got

I think the compressor has a safety on it that it wont run unless there's an appropriate amount of refrigerant in the system. I *think* this is right...

Aufgeladen944 · 05-10-2007, 05:12 AM

Well there's practically nothing in it at the moment, and I have more of the R-134 and the recharger kit, and the I changed the port to allow the R-134 to be used.

But, once I put in more of the R-134 I don't think the compressor will turn on. It seems like there's something I have to switch to turn it on. As in, the safety doesn't just automatically turn off.

I don't think there's any leaks; I evacuated the old freon myself already.

mattdavis11 · 06:53 AM

You can jump the low pressure switch to get the compressor to engage. You will find it in line near your dryer. The dryer is the canister that has a sight glass on it.
If that doesn't make the compressor run, you have another problem, probably electrical. You can also run 12V straight to the one wire that comes off of the compressor. Do not run it very long this way if you don't have oil in the system.

I have to ask, how in the world did you evactuate the system yourself? Did you just let it loose? If you did, you need to get the remaining stuff out with a vacuum, and see if the system holds a vacuum.

Oh, and Eldorado said, a flush would be a good idea too. You can clean out the lines with denatured alcohol and compressed air.

Aufgeladen944 · 05-10-2007, 07:16 AM

Yeah I just used a pen and let it loose. It sounds like I'm in over my head lol. I always thought that was how you got the old oil out of it? I know it's not technically legal, but...

For the record, air conditioning systems suck.

mattdavis11 · 05-10-2007, 09:01 AM

Yes they do suck, always on the low side, which is where you charge.

I've know some people not to completely evacuate the system and get good vent temps. YMMV.

Eldorado · 05-10-2007, 09:29 AM

that will work to vent the freon gas, but not the oil. the oil should be changed.

and it wont get all the gas out with a system that isn't running. it needs to be on to vent the gas. Or like mat said, a vacuum needs to be placed on the system.

I've heard that mixing 134 with the oil for r12 is a bad idea.

instead of using 134, use a refrigerant that is compatable with R12, like Duracool.

and if your system wasn't blowing cold, then you have leaks, or a mechanical/electrical problem. freon doesn't just disappear or go bad. putting a vacuum on the system will tell you this.

oh, and make sure you're charging on the right port. like Matt said, make sure it's the LOW side.

Aufgeladen944 · 05-10-2007, 11:13 AM

I had the car running when I vented the old gas. I think most of hte oil that was in there came out, too. My mechanic said there's pretty much nothing in there right now. I've been charging it on the low side, but I think I evacuated what I put in there anyways.

It was blowing out sort of cold before, just a little cooler than the ambient temperature. It was 85 degrees a couple weekends ago; I'd say the air coming out was around 65 or so. It wasn't quite tolerable to have that on and not have the windows down. I could be wrong; maybe it was just the fan cooling me down a little bit and the a/c wasn't working at all.

I'm out of the R134 anyways, so I'll pick up some Duracool.

agentmacguyver · 05-10-2007, 02:32 PM

I'm trying to charge my system too, and have an r12 substitute. Unfortunately, the compressor is not running, so I'm going to need to "jump" it. How do I do that? Do I just locate the pressure switch, disconnect the connector and short the wires? Or is there another procedure?

Also, where is the LOW pressure port? It seems there are TWO ports on the compressor. One that is hidden way up on top and can barely be reached by the tip of my finger. If it's that one, this is going to be nearly impossible!

agentmacguyver · 05-10-2007, 03:56 PM

Alright, I'm back with an update.

The port that was visible on the side of the compressor was, in fact, the low pressure side. I was confused because it was high pressure with the engine/ac turned off. Once I turned on the AC, the pressure dropped to under 10 psi. (Apparently my compressor was turning on, though I couldn't tell)

I added a can of leak stop with oil and a can of coolant. It's blowing very cold now. I didn't want to add more, even though there are a lot of bubbles in the sight glass, because the forums for the stuff I used said I need to use less than the original freon. If it doesn't feel cold enough, I'll plan to add more later.

For everyone who's curious, here's how I recharged my Porsche 944 S2 AC:
I used Freeze12 (ebay - $60 for a complete kit w/ gauge) and just added it to what was in there. I called the manufacturer, and they said it is completely compatible w/ r12. Though of course they recommend evacuating the system for environmental reasons. But my system was already contaminated because the previous owner added an r12 substitute 2 years ago.

The low pressure port is on the side of the compressor pointing toward the ground. So, I had to jack up the car enough to get under it. There is a hose connected to the back of the alternator that is easy to remove, and makes access much easier.

From there, the schraeder (sp?) valve should be visible. I added the Freeze12 until the gauge was at a little over 30psi. System was blowing very cold at that point.

I meant to take pictures while I had it apart, but was distracted as I was heading in to get my camera. Then I remembered again after I had put everything back together and put away the jack. Next time.

I'm thrilled to have cold air again!! Good luck to everyone else!

mattdavis11 · 05-10-2007, 04:42 PM

Your sight glass is no longer useful when you use duracool or freeze 12, so don't use it as a reference. You will never get rid of the bubbles. If you do add more, you run the risk of blowing hoses.

Eldorado · 05-10-2007, 05:10 PM

give us an update in a few days/weeks as to how it turned out and how that leakstop is working out for you

phoenix_iii · 04-18-2008, 05:33 AM

and pics!!!

many944s · 04-18-2008, 06:01 PM

I don't mean to be a stick in the mud but.....
From the voice of someone running an EPA 609 certified shop, I would suggest that you edit your post about venting your old R-12 to atmosphere. Where as I could always use the money, I wouldn't report a fellow Pelican.... But as this is a PUBLIC forum, anyone could see your post and there is a sizable fine $$ for venting R-12. And yes, there is even a bonus for anyone reporting the venting to the EPA. Unfortunately your post is a great admission.

As I said I don't mean to be a d***, just watching your back!

-Nick

John_AZ · 04-19-2008, 05:16 AM

AC posts are getting common again. My AC R-12 mechanic/technition will NOT put in a stop leak. His explanation is that the stop leak will gunk up the system. If the system is low-not empty, he charges $5 an ounce to top off plus setup. Needed about every 2 years-2006 prices. I run my AC every couple of weeks year round to keep the seals oiled.

John_AZ
1988 924S + 1987 924S