Reconditioning my air conditioning - tips?

Z06C5R · 05-30-2008, 03:34 PM

Now that it's starting to get hot out, I think it's time to give my semi-functional AC unit a good once over... Being completely new to AC systems, I'm going to need some guidance:

The first issue I have in the system is the blower... It functions intermittently at best, and often won't turn on at all. I did notice an odd occurrence today in relation to said blower - I had it switched on on my way home from work hoping it would come on at some point (which it didn't). When I got home and turned engine off, the blower came on. Later in the day, it was running good until I switched it off accidentally, and then it wouldn't come back on again. It would seem to me this is an electrical issue, which I'm notoriously bad at diagnosing and fixing... Any tips?

Also, the system clearly needs to be charged again since the air that blows out of the vents is never any cooler than ambient. I did a quick search and it looks like the easiest thing to do would be to get some kind of recharge kit that's compatible with the old R-12 stuff that's likely to be in there. I'm assuming that there's a leak somewhere (though the PO was adamant that nothing leaks) - what's the word on running some kind of leak-stop through? Any other suggestions - Again, this is my first time working with an AC system, so I'm totally new to all of this.

mattdavis11 · 05-30-2008, 06:34 PM

Refresh my memory on the 85/1 car, I think I gave some bad info a few days ago on a 924s. Does it have a dial for the a/c and fan speed between the oil pressure gauge and the clock, or is the a/c button opposite the shifter from the radio fader and placed in the same manner?

On my car (83), the a/c fan shuts the fresh air draw and fan down completely. Maybe the 85/1 doesn't have two fans, I forget.

As for the charge, you've heard it before, you have a leak, somewhere. Whether or not a charge will get you by, who knows. I'd buy an ounce or two of dye'd ester oil, and some R12 substitute and throw it in the system. At worst you can find the leaks with the died oil, or try my famous leak detector, soap and water. Look for the dye being expelled, or spray s&w on all lines and fittings, including schrader valves.

djnolan · djnolan's Garage

There is a good explanation of how the vents and blower controls work on Clarks. Suggest you start there and check all functions of the climate control system. I would satrt here before comitting funds to recharging or leak repair.

If your engine is fairly clean you should be able to find a leak without dye by just looking for oil on the lines and fittings. But dye will make it show up for sure. A likely place for a leak is the o-rings for the two hoses that connect on the back of the compressor. If the back of your compressor is messy, you probably need to replace these o-rings.

If you can find the leak before you have to pay to get it recharged, that is better and will save you $1-200. Also, if you are replacing R-12 with Freeze-12 or something I think the system needs to be evac'd first. If you are going this far, might consider replacing the receiver dryer, the cylindrical thing behind the left headlight.

Z06C5R · 08:00 AM

I did read the thing on AC function at Clarks, which was very informative on the function of the system, but didn't really point me anywhere specific - especially concerning the blower issue. I'll take a look around today and see what I can find under the hood.

One more thing: What are some brands of refrigerant kits that I can use with the existing system / refrigerant... I understand there are R12 substitutes out there, but everything I've found thus far is strictly for 134a systems which of course have a different fitting.

88BlueTSiQuest · 05-31-2008, 08:30 AM

I'll tell you this, based on my experience. Don't waste your money on any 'off the shelf' recharge kit you'll find at Walmart and auto-parts stores. If there is air in the system, you won't have good results. If you are low on freon, then you have air in the system.

The system needs to be vacuum out, and any remaining freon and oil need to be reclaimed. After that is down, they generally can test for and locate leaks. Once the leaks are taken care of, it's usually cheaper to put in R-134a, but don't expect it to be anywhere near as cold as R-12 is capable of.

I had my old Quest switched to R-134a, and was never happy with the results during the hottest days of summer. The best way to switch to R-134a and still have a cold A/C system is with a new compressor capable of more coolant flow.

IIRC www.944online.com had compressors that were made for R-134a, and the kit with compressor and all was relatively inexpensive.

John_AZ · 03:36 PM

www.Griffiths.com has parts for the Porsche AC system. More valuable is the AC help section:
http://www.griffiths.com/achelp/

And here is another site to help you with either R-12 or R134 conversion (has technical bulletins). Click on either topic: http://www.the944.com/.

John_AZ
1988 924S + 1987 924S