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Hey Carpokes!!
I did something maybe not the brightest when I was making room for my timing belt change. I needed to move one hard pipe a little to get one of the pivot bolts out of the way. Usually I’m super careful to see what I’m moving/ loosening but stupidly I loosened this on pipe a little too much and let some “ air pressure” out. Afterward I saw it was the AC LINE. I tried to look up if what I did was a big deal , little deal, or no deal but really couldn’t find the specific answer.
I seem to have R-12 Ac system based on what i see on the unit. ( see pic)
I guess my question to you guys is what should I do next ? Is this a AC Recharge issue ? I didn’t turn the AC on since the incident.
Thanks for the help. I’m really not versed in AC stuff.
IMG_1729.jpeg (3.16 MiB) Viewed 96 times
This pipe the hard pipe , not the blue port was loosened and pressure released.
nagykurva wrote: Tue Apr 14, 2026 6:00 pm
Hey Carpokes!!
I did something maybe not the brightest when I was making room for my timing belt change. I needed to move one hard pipe a little to get one of the pivot bolts out of the way. Usually I’m super careful to see what I’m moving/ loosening but stupidly I loosened this on pipe a little too much and let some “ air pressure” out. Afterward I saw it was the AC LINE. I tried to look up if what I did was a big deal , little deal, or no deal but really couldn’t find the specific answer.
I seem to have R-12 Ac system based on what i see on the unit. ( see pic)
I guess my question to you guys is what should I do next ? Is this a AC Recharge issue ? I didn’t turn the AC on since the incident.
Thanks for the help. I’m really not versed in AC stuff.
IMG_1729.jpegIMG_1531.jpeg
How long did it hiss before you tightened it up? If just a second or two, I'd guess you're fine -- probably less than an ounce escaped. If it hissed for a minute or three though, that's a different story... I'd try the A/C and see if it's still cold, assuming it was before. Worst case, you'll need to have the system evacuated and recharged, which is not that big of a deal -- but for the fact that R12 is getting mighty hard to find, and finding shops willing to work with it is even harder. Most shops want to convert to R134a. On the 944, you can make that conversion without much/any decline in a/c performance, but I defer to the 928 folks here on whether the 928 is as forgiving....
nagykurva wrote: Wed Apr 15, 2026 6:48 am
Thanks Tom!
Unfortunately it was more than a few seconds… I pretty much released all the pressure .
I’ll give the AC a try when I have a chance.
If anyone knows R12 recharge source would appreciate the help.
Kevin
Ah, in that case, sounds like you'll need to have it evacuated and refilled. R12 was banned some 30 years ago, so it's quite a challenge to find. You 'can' find left over supplies on eBay, but the price just keeps climbing and the cans just keep getting older. Technically you also need to be certified by the EPA to buy it (though not all sellers care/know about that). See, for example, this vintage can that will set you back nearly $50 after shipping....
I'm not aware of any shops in my area that will still refill r12 -- most shops will suggest converting to r134a. I resisted that for years until finally biting the bullet and converting. Done right, the a/c can be as cold as ever. R134a conversions have kind of a bad reputation though, since so many people try to cut corners in their driveway and end up with weak a/c. I have no experience with the 928 though, so can't say for sure how much extra effort (i.e., new condenser?) is needed to make it work really well.
One other word to the wise, beware of all the hydrocarbon refrigerants sold on eBay as r12 replacements. They are basically propane in a can, with all the predictable safety risks. It's illegal to sell that stuff as an r12 replacement for cars, but they get away with it using sketchy ad wording and lack of enforcement. They are all over eBay -- making it even harder to find the actual vintage cans of r12 -- so if you go the eBay route, be very careful what you buy.
I can safely say "been there, done that" and I have freezing AC as a fringe benefit.
The bad news is that you did lose some AC charge. The not-so-bad news is that your pictures show a blue R134a service valve cap on that suction line above the compressor. It has had a conversion sometime in its past, so you should be able to take it to a regular AC shop for service. They may try to claim a "Porsche tax" multiplier, but for no reason really. The system is easily serviceable now, with service ports pretty easily accessible. The compressor is a very popular Denso unit too. Nothing you wouldn't find on a Toyota really. Other components are common Behr pieces fitted to other luxury European cars at the time.
Some more perspective --
-- The line in your picture is in fact the original suction hose, spec'd for R12 service. The replacement refrigerant has smaller molecules and, at least theoretically, will slowly seep through the hose wall. But a well-used R12 hose also has some oil soaked into the hose lining, and that seems to dramatically slow the loss of charge.
-- The o-rings needed for R134a are different from the original R12 o-rings fitted at the factory. The challenge is really with the oil needed with R134a, where PAG and often Polyolester refrigeration oil replace the common mineral oil originally used in the R12 system. I spent the best part of an afternoon replacing o-rings and rebuilding hoses when I converted my car way back when (almost 30 years ago now...). I also missed a couple, which became evident in less than a day when they failed in a rather surprising way. Question is whether those o-rings were swapped on yours, with a particular concern for the connection you loosened. If you don't know the material status or condition of that particular o-ring, there's a good case for checking it before you go through a full evacuation and recharge. Even if it is the correct material, rotating the connection under pressure may have scuffed it. The evacuate and recharge effort is the same regardless. Consider that the connection will never be more accessible than it is right now, with the fan console and usually the radiator already removed for your timing belt service. If you do find an original black o-ring there, your whole conversion is suspect.
For others playing along at home: From Tom's reminder of some bleak history of R134a "conversions", many conversions, especially DIY efforts, were not done correctly or completely. From leaks to oil contamination, to procedural errors like not fully evacuating air before adding refrigerant, many reported center vent temps in the mid-50º range. Cool but not cold. Meanwhile, a proper conversion offers similar performance to original. We lived previously in the Socal desert climate, and retired to the high desert of central Oregon. I bypassed the freeze switch to get max cooling in a heat-soaked black 928 above Los Angeles, and managed to have mid-teens center vent temps cruising on 90º+ days. It will freeze fingers on the steering wheel.
Let us know what you find. For sure the recovery from the leak will be a whole lot easier than if it still had R12 in it.
dr bob wrote: Wed Apr 15, 2026 10:16 am
The not-so-bad news is that your pictures show a blue R134a service valve cap on that suction line above the compressor.
I looked at that and it seemed kind of black and Porsche-y..., but I guess the metal adapter under the cap is the tell?
The original R12 caps are much smaller, black, and have a domed top shape. The R134a suction caps are blue with the ribs, while the smaller high-pressure side caps are red. The ring for the adapter under the cap is another clue.
Those caps, along with plastic dipstick handles and oil caps, scrub clean with some Comet and a stiff brush, a bit of hot water, and seven ounces of elbow grease. It pains me to see perfectly good plastic caps showing a lifetime of greasy-fingers staining, even in a well-detailed engine bay.
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I spent a couple hours under the front of mine yesterday, cleaning up a small bit of tensioner oil seepage right where the OP pictures that AC hose. A bit of Dawn and hot water in a small pump sprayer took a while, and only after some more serious paper-towel wiping, and some time with the scrub brush. Then a distilled water rinse. It's a ways from white-glove ready, but way better than it was. Same car I did the belt on 3x before I found the poor connection from the warning contact. The dribble is from that same work, when I pumped it too full of STP a bit over a year ago, trying to stop the warnings. The goop finally made it to the undertray and the floor during hibernation.
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More - just revisiting your pictures, the label on the compressor shows it has Denso 6 oil, which is PAG should the question come up. So it's a native R134a compressor, a Good Sign. You don't share the year of your S4, which can sometimes be a help.
Those caps, along with plastic dipstick handles and oil caps, scrub clean with some Comet and a stiff brush, a bit of hot water, and seven ounces of elbow grease. It pains me to see perfectly good plastic caps showing a lifetime of greasy-fingers staining, even in a well-detailed engine bay.
Just 7oz. Don't spill any. That stuff is expensive these days
Lots of good information in here
Woah, I had no idea there were black cap and blue caps. I have started to look into purchasing a conversion, but my car has blue caps... does that mean it's likely already R134a?
Also curious if the red "putty" in the bottom of the photo means someone tried to stop a leak? I assumed as much...
. 
) but I’m happy to take out if needed.