Steve J.

What's the best way to locate a refrigerant leak? UV dye or electronic sniffer?

zoltan944

stop leak with dye, prolly wont leak anymore after the stop leak anyway, but if its THAT big of a leak then the uv or red dye will show

Gretch

Where is stop leak with dye sourced?

zoltan944

well, if you have R-12 still you will have to find some from someone who has r-12 and supplies and such. May need to go on ebay or something. if you have r-134, anywhere(even walmart). I convert all my systems over to 134 or r-12 substitute for cost and ability to do things myself

zoltan944

This guy has everything on Ebay
i have bought alot of stuff from him, he carries R-12, R-134, autofreeze, and everything else you can think of. The link above is directly to R-12 stop leak with detector

ROG100

Steve,
If the system still has pressure in it (check with your gauges) use a solution of washing up liquid and water and smear some of the solution in the likely places to try and locate your leak.
I have a recovery system for R12 so if we need to charge with R12 we can recover it once we have located the leak. You will then need to change the dryer and vacuum the system.
I have a sniffer if you want to borrow it, however I have had much better success with the bubbles.
Let me know if I can help.

Steve J.

The AC hasn't worked for 6 months. It had some pressure and I charged it up last week with R134a. It took one can to get the compressor running and another can to bring the pressures into the correct ranges. It only lasted about a week. I've been all through my system about 4 years ago when I converted to R134a, replacing every o-ring (except the compressor shaft seal). That one would be hard to see with soap bubbles. I'm leaning towards dye. Does the stop leak stuff gum things up? Maybe I'll try it.

zoltan944

i have had GREAT success with stop leak! try it out!

Earl Gillstrom

DO NOT, DO NOT, EVER put stop leak in an AC system. No reputable AC service facility will ever work on your car again. The first thing they do is use an identifier. Use only R12 or R134. Be careful, most R134 sold in Wallyworld has stopleak. The fix for stopleak in an AC system is to replace the complete system to eliminate it. 928s leak refrigerant. It says so in the owners manual. R134 will leak faster than R12 since the molecules are smaller. It is not wise to put R134 in a 928 designed for R12 unless you like adding R134 every few weeks. With R12, there is about 6 extra ounces of freon that can leak out before you notice any degredation in performance. Please don't destroy your 928 with sealer.

zoltan944

most 'reputable' shops don't exsist. i have been around the automotive repair industry my whole life, that is why no shop will touch my car. i do almost everything myself, including AC. i have had great success with R134 and stop leak in cars including 944s, 924s, and 928s. the only thing it can even ruin is something that needs to be replaced anyway. Once again i guess it all comes down to how much money one wants to spend

slate blue

I have fixed plenty of air cond systems in the 928s. Put a dye in it and then check it in a dark garage with a UV light. If the hoses are originals they will be leaking. Also the front seal on a compressor is good for 5 years I have found. S4s also leak in the rear evaporator. Also check in the floor where the pipes go through to the evaporator. If they salt the roads where you are maybe the condensor is leaking. This is starting to happen in the U.K. Check the TX valve in the back of the engine bay also a culprit.

The cars I have fixed, didn't need a regas for years, that is because I did the job properly. It does cost quite a lot to do it this way though.

Larry928GTS

I've heard a few times already that the expansion valve is a fairly common leak point. Is it the connections to the valve that typically leak, or the actual valve itself?

JPTL

I found that the rear expansion valve can get crudded up, even if the front looks good. Probably from poor circulation and lack of use of the rear a/c. A crudded up expansion valve will likely promote a leak at the connections, so a leak check at the rear expansion valve is a must.
Also, those basic battery op. UV lights can be had for less than $20 online. They are considerably weaker than the ones that the a/c techs use, and you need to be in total darkness, but if you have dye in your system, these little lights will pick it up.

SteveG

Greg: I had a leak at the rear connection under side of car. I open up, cleaned the fittings, replaced with new green o-rings. It still leaks; outside of replacing the fittings what would you do? Use next larger size o-ring? I don't think I damaged the ring during the tightening process, but I remember it was not easy getting the snout inserted cleanly into the floorboard fitting; I thought I had an exact match on the replacement rings.

My other solution is to tie off the rear altogether. A refrigeration tech, not a 928 guy, recommended not to do that as the capacity of the system might need that to function properly. Seems that if the system is reduced to front only, you just adjust the amount of freon to that of a front only system. I think the diff is 37 oz to 33 oz.?? Anybody?

Steve J.

OK - no stop leak- but-
Why not? What's the harm?
(btw- All hoses were rebuilt with barrier hose.)
If I have to open the system, should I convert back to R12?