Renwaltoys

Have a slow a/c leak where I must top off system with a pound or two of R12 every two years or so. Has anyone out there had any positive experiences with the sealants that are added to the system that you see advertised? Thanks for your input, Duke

hope2

have you tried to find the leak? stop leak certainly will have mixed results. maybe if you know it's the evaporator it's worth a try, otherwise no.

Renwaltoys

Thanks for your reply. While I have an excellent mechanic who maintains are car he doesn't do a/c. I don't have anyone in the area that I know of that still does R12 that I would feel comfortable with so if necessary I will just top it off every couple of years. Thanks again for time, Duke

emdoller

I feel your pain. It's hard to find anyone in my area that knows old AC systems. I've had to learn it on the fly and with a lot of help from folks on this forum. With that said, most AC shops should be able to find the source of the leak. I've personally used freon sniffers and now use UV dye in my oil instead.

If you are uncomfortable taking it to an AC shop, I'd suggest the next time you add R12 you add some UV dye.

Good luck.

Ed

Renwaltoys

Thank you very much Ed.

cblankin

If you are leaking R12 you are probably leaking the oil that is in the a/c system. If it is leaking out the compressor chances are it is being slung out and being deposited on the backside of the hood. It will leak thru the hood and cause the paint to bubble. It is probably time to convert to R134. R12 is nearly impossible to find and very expensive when you do.

emdoller

I certainly don't want to start a 134a vs R12 debate but you can find loads of r12 on Craigslist and eBay. I pay $20-25 per can and feel it's worth the extra to keep it original.

Agree you should check your hood. If you ever do want to have your compressor rebuilt, search for Dom on this website. He's done great work for many of us.

Ed

Milliamp

Have you seen any sign of wetness (i.e. oil that has leaked from your system) If you find this you have found your leak. What you do with it now is the big question, If it's the compressor and needs new seals my advice repair it R12 does a great job of cooling ,I think its a lot better then 134 I would not under any reason inject dye into the system. Many will debate that the expansion valve will not be effected, why take a chance.

Tom

Milliamp

Have you seen any sign of wetness (i.e. oil that has leaked from your system) If you find this you have found your leak. What you do with it now is the big question, If it's the compressor and needs new seals my advice repair it R12 does a great job of cooling ,I think its a lot better then 134 I would not under any reason inject dye into the system. Many will debate that the expansion valve will not be effected, why take a chance

emdoller

Yes, UV dye is another religious debate. Everything I've read says it's fine.

Ed

Powershift

Ed:

Just purchased a new 2017 Silverado truck. Noticed yesterday that it uses refrigerant R1234yf. R134a is now obsolete for use in many new cars.

Larry

EDIT: I have stated many times that keeping these older AC systems working is a labor of love, and you need to do much of it yourself. So buy a decent refrigerant leak check tool (Inficon TEK-MATE or similar) and get a bottle of SNOOP soap solution and go find the leak. It is not a hard process. You will probably pay equal or more $$$$$$$ to someone to do this job that it costs for the equipment I stated. And you will always have the equipment to use later on as needed..........or to help your friends.

hope2

Again I would attempt to find the leak, sometimes it's obvious. AC specialty shop could certainly save your freon, fix the leak, be sure your system is filled with oil, recharge and check. Worth it. Good luck.

karkrafter

I've never seen a sealant that works, The loss of a pound every two years is MORE than acceptable...how much $$ do you want to spend to save $15 a year in coolant...

Renwaltoys

Never any wetness present on the hood. No obvious leaks. Thanks again for your response, Duke

emdoller

FYI: Larry has helped me immensely!! He's my go to expert and has helped me with my Vette and recently with my Camaro. I now feel comfortable handling my AC issues. I also agree that it's a good idea to figure out how to do it yourself.

Ed

Powershift

Duke:

Check your Schrader valves and make certain they are tight in their fittings. They can leak refrigerant if they get old and tired or are loose in their housings..

Additional leak sources are hose porosity and hose end connections, o-rings, compressor front seal, evaporator core, and condenser core.

Electronic leak detector is best for compressor seal, evaporator, and condenser, and hose porosity. But it can also become overloaded if you have a large leak.........then you need a big fan to sweep the air clean of refrigerant before testing again. SNOOP leak solution is great for all the o-rings and end fittings and also the hoses.

Back in the day, loss of one 12 oz can of refrigerant every 1-2 years was the norm and was considered acceptable.

FWIW.

Larry

domenic tallarita

Had a long talk with Powershift last week who I think is expert on the systems among a few others here.
I don't think your leak is from a overcharge condition because your gas is leaking to a under pressure condition.
What I would like to say is that many oil leaks can be caused by the installer such as gas overcharge and oil overcharge.
I haven't found any ceramic bad on compressors sent to me but I think the main culprit could be the main shaft seal which is nothing but a O-ring. The O-rings do not spin on the shaft with a ceramic seal the O-ring only seals the place that gas & oil can leak out of the compressor. A lip seal seals more with pressure but the O-ring is only making contact on the shaft.
So I am thinking that a over charge in gas or oil can cause a leak in some compressors. The unregulated oil pump oils thru the main shaft thru 3 ports. one for the rear bearings, one for the front bearings, and the last is directly in back of the ceramic shaft O-ring.
The higher the RPM the higher the oil pressure. The oil pressure cannot be measured but is not regulated with a by pass system. The pressure in the case along with a oil pump adding to it on that poor O-ring may be able to blow oil past it in a overcharged condition with either gas, oil, or both.
Now even though the book says a little leakage is normal, they installed a oil level plug on the side of the pan. They call it a drain plug which is part right. It is actually a oil level plug that is designed to drain off excess oil without loosing gas pressure. That tells me that to much oil is not what you want and may be causing a leak.
If your compressor is leaking and you suspect either one of the causes it would be a good idea to put a set of gauges on it first before sending a compressor out and checking the oil in the compressor pan which is outlined in the manual.
Just a thought.

Dom

Renwaltoys

Larry,
Thanks so much for taking the time to share your thoughts. Last year I bought a 30lb R-12 which we used for the first time yesterday. While I would like to conserve it as much as possible if figure at my current rate of loss it should take me out till I am almost ninety. By then who knows?
If I would have gotten more positive feedback on the current stop leaks I might have tried them but as one of the other members said you have to weigh the cost of finding the slow leak to the price of adding a pound or two of R-12 every couple of years. Again sincere thanks for your concern and if you don't mind I will keep your name on file for future refererence. God bless and a Happy Fourth to you and yours! Duke

GTOguy

Find and fix the leak. Most likely a compressor front seal. The stop leak softens seals and lets them work for a while, but the softening actually degrades them and breaks them down. (think over-marinated meat). A properly repaired and charged system will last you many years. The UV dye used in leak detection causes zero issues.

Renwaltoys

Thank you so much for your useful comments, Duke