GREGGPENN

About 5yrs ago, my 89 finally showed signs of A/C issue. I bought 3-4 cans of Freon off this forum but it only took 1 can to solve the problem. That might have been 2014?

Last fall, same thing though I didn't notice until fall. As such, I didn't service it. Now, it doesn't blow cool air at all. Can't say I SEE where the leak was/is. I guess it could be in the evaporator or condenser...or maybe a super slow leak around an O-ring at a joint?

Finally found a local shop that still deals with R12. My car has 85k and (as many) is garaged. (I suppose that's how it lasted nearly 30 yrs w/o major A/C problem.) This local shop says $150 (labor) to fill -- when I come up with the R12. They don't have any. (Craiglist can get me cans in the $22-$30 range OR one guy has a canister with 13lbs in it for $200. Gotta wonder if it's possible the canister has water or is contaminated?)

This same local shop quoted $350 for a "dirty conversion" to 134a. I think that means replacing ONLY the fill nippes...which seems like a rip AND a dumb idea. This shop said it would be the way to go "To get it over with". But, I see leaks just as possible -- so it doesn't solve anything.

Who votes I should buy the canister? Who thinks I should (just) buy a couple more cans and refill -- with dye -- to find the leak and proceed from there? With such a slow leak, are you thinking O-ring to fix...with potential for a few more years of service?

I'm posting because I don't see any post outlining possibilities and/or options for repair. They only thing I can say for sure is I'm not flush where I can spring for a complete conversion right now. Nor would I want to go that route unless it seemed unavoidable.

PatternDayTrader

I would just put a can or two in and run it until I felt like I knew for certain where the leak is.
The reason being is if turns out to be say the evaporator or condenser then you might as well bite the bullet and do the total conversion at the same time you replace said component.
But, if its something stupid like a leaking Schrader valve at a test port, then just get that fixed and don't worry about converting for now.

confab

If you're reasonably handy with the tools, you can do the R134 conversion yourself and do it right. (Better than their "dirty conversion" sounds, anyway.)

The best answer I ever saw on this question is the following from JoeC.

https://www.corvetteforum.com/forums...post1594932215

I did it to mine, and it required an oil change, new canister, a wash out, new fittings, a seal kit and a cycle switch adjustment.

All told, it was about a hundred bucks, maybe?

There's more to it than just replacing refrigerant. The book is excellent and explains it all. The kit from them, including the book, fittings and oil, is available on Amazon and I think I payed 20 bucks for it?

Good luck!!!

Benny42

I'm not a fan of the dye products out there. My personal opinion is that the dye is a contaminant. Real R-12 is THE easiest refrigerant to detect with an electronic leak detector with those fat chlorine atoms. Find one in a pawn shop and haggle. To answer the drum question - if the drum is a disposable and has a green plastic valve stem (handle/****) it has a check valve and you can't put anything back in them if the drum hasn't been welded on. A black **** (very old) disposable has no check valve and may have anything in it. Any returnable drum, same warning, no check.

jv9999

This is what I did on my '87. Still working great 3 years later.

aklim

I'd buy the canister and find someone with a sniffer to detect it for you or use dye.

polo91

I vote for a conversion. My 91 blows high 40 to low 50 degree air with outside temps at 100, highway or city. I knew where my leak was because my condenser was damaged. Bought a used unit, removed the compressor, blew acetone through everything to clean out the old oil. Replaced the filter/dryer, orifice tube, R134 ports, and o rings. A little time consuming, but cheap. You will need a vacuum pump (cheap at Harbor Freight) and just add oil and R134 until it's cold. A year from now if it is a little low, no big deal, Walmart 134 $5. By the way, soap bubbles are the best way I've found for leak detection.

-=Jeff=-

If it is leaking, I would suggest pulling vacuum and leaving it sit to see if the vacuum drops.. I ended up replacing all the seals and the High side schrader valve. as it was a source of the leak. Once I confirmed it held vacuum for a few days I then charged with R-12.. still working today and I know I charged it prior to 2013

84 4+3

My r134 conversion, just the ports, blows around 38...

My system was also completely dry when we bought the car so it was easy. R-12 is a better charge but the system is oversized enough that 134 works almost as well in my experience. The ability to reject heat of r12 is roughly 10% better at 90 degrees if I am remembering my schooling right. If you can get the r12 reasonably and fix the leak I'd do that.

GREGGPENN

My neighbor has a gauged fill set...so that helps. He also said he could borrow a vac pump. So...that's a starting point.

We read (online) about R12 (R12a and RS24) freon substitutes for R12. Are they really as good as advertised?

Looked at vids (for conversion to 134a) on Youtube. Didn't seem extensive enough because none talked about conversion of the condenser. Thought that was a big help to make 134a work well?

I wonder what's in the book linked in post #3...that I might not find on this/other forums? Or...Youtube?

Seems like I should partially fill and have sniffed...Or maybe totally evacuate and test for vacuum...except it sounds like a fill is necessary FIRST to find any leaks? How "empty" would it need to be before "declaring" a total evac necessary to clean/dry and add oil?

On the canister option, I started wondering how I'd know if the R12 was pure...or even genuine?

xrav22

The condenser is fine, but I believe the orifice valve is gauged a little different for flow.
I am using the 37 year old condenser and even though the openings are larger they still work. I would try to fit new Schrader valves and mabey a high cutoff switch for safety.

GREGGPENN

I did a search and found that the ONLY other can of freon was filled in 2013. So....It took years to get 1 can low (owned the car since 1999) and ANOTHER 3+ years to leak that can back out.

How can I say that?

Put my neighbor's gauge on it. The low side showed a bit more than ambient pressure...as mentioned. IOW...It still had SOME freon in it. He couldn't find his adapter for the high side but I found my old-fashioned single line R12 filler hose (from the 70's). We only put 1 can in and it's blowing 35-deg air on an 85-deg day with high humidity. IOW...it's seems like 1 can was enough to restore proper operation.

Guess I'll keep an eye out and look for signs of a leak. Maybe drop by a shop to see what they'd charge to "sniff" it? And, of course, see how long THIS CAN lasts before it starts triggering the low-pressure sensor.

The reason it wasn't cooling AT ALL was because the compressor wasn't running. I'm assuming (w/o pulling my FSM) that a low-pressure sensor cuts off the compressor. (Plus, my neighbor said so. LOL) As we added the freon, the compressor started running longer and longer until the whole can was sucked in...and the vent temp got down in the low/mid 30's.

gerardvg

Hi

The common leak points are the O rings, compressor shaft seal or the a/c cooling fan request pressure switch (the small found plug one on the liquid line (small alloy pipe from condenser to a/c box and orifice tube). It will have another safety switch with two spade terminals beside it that is for high pressure cutout.

Oil will usually be visible when the compressor shaft seal leaks, flinging oil onto the hood.

The a/c cooling fan request switch can leak right through the round electrical plug, i have had two leak there..... even a new one ..

Use an electronic leak detector or detergent spray and look for bubbles, if you are going to use a dye use it sparingly.

As far as using R12 go for it if you can get it, R134A works fine however you have to drain all the oil you can from the compressor and replace with Ester oil.

Ester oil is for conversions and will mix with any mineral oil that cannot be removed, replace the black rubber O rings with the green type for R134A. You can buy screw on adapters for R12 ro R134A conversions that will screw onto your old R12 ports.

Charge with 80% or R12 charge with R134A, I have an 85 and the standard condenser works fine.
Has been around 10 years without a problem.

Oh yeah ..... don't forget to run your a/c year round, at least a few times a month to keep the O rings and compressor shaft seals lubricated to keep the refrigerant from leaking out.

GREGGPENN

I will give it a few days and reinspect to see if I can see obvious signs of leakage. Maybe load a sprayer with detergent...to create bubbles.

Without the aide of gauges, who thinks air duct temps in the 30's (at night) is indication that 1 can is enough? Versus who thinks the low-pressure switch would activate with "only" a 1 can void in the system? Trying to get an idea how full it might be based on feedback of what it takes to be low...and trigger sensor shut-down versus how full it needs to be to hit 35-deg vent temps.


Edit:
Put another way....How many ounces would you guess are between a "full system" and low enough levels to create failure to cool via low-pressure-prevented-compressor-operation?