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R-4 leaking, rest of the system is 32 years old - replace everything?

Jonathan on Mon July 14, 2014 8:53 AM User is offlineView users profile

Year: 1982
Make: Chevrolet
Model: Caprice Classic
Engine Size: 4.4
Refrigerant Type: Freeze-12
Ambient Temp: 80
Pressure Low: 45
Pressure High: 185
Country of Origin: United States

A little background about my Caprice - I had the A/C evacuated and recharged with R-12 about 12 years ago when I could find a place that would still touch it. Before that, the system wasn't working at all, but the car was new to me at that time. I'm assuming that it leaked out over time, which wasn't unexpected considering the car was 20 years old at that point. That charge lasted me about 3 years before the compressor was short cycling and wouldn't cool the car. I was broke and didn't know better, but needed A/C since my job required me to drive long distances and the power windows didn't always work - I bought a few cans of Freeze-12 and a cheap gauge set, and charged it myself. The parts store said it was a drop-in replacement for R-12. That restored cooling, and lasted for about 2 years, maybe a little less. When the compressor was short cycling again, I bought a case of Freeze-12 (it was cheap then!) and kept re-filling the system (usually filled until it stopped cycling on low pressure plus about 4 psi) when needed because I couldn't afford a complete new system, or even a compressor. Nobody I took the car to was able to find the leak, even with dye in the system.

This all brings me to now. I'm out of Freeze-12 now, but more importantly, I want to do the repair right. It looks like there's a bit of oil buildup around the original R-4 compressor, so I'm assuming that's leaking. The high side pressure didn't seem to get as high as it should last time I charged it (those numbers are from what I remember last time I charged it), and due to the age and slight rattle it makes, I don't know if I'd feel comfortable trusting the compressor.

Everything in the system is original, never been opened, down to the orifice tube and accumulator. The condenser and evaporator seem to be in fine shape, few bent fins and no oil residue as if they were leaking. Should I try to re-use them, or due to the age and past history of the system, just replace with new? Will the old parts properly re-seal whe connected to new lines? It looks like all parts I need for a complete system replacement are still available from AMA.

Also, is there a good source for R-12 anymore? I'd like to get a 30 lb jug to be more precise when weighing in the refrigerant - I've got a few other cars that take R-12 still, and everything with R-134A has been too reliable or under warranty. I don't know if I trust something from Craigslist not to be propane. How much R-12 should I use? The sticker that said how much to refill the system with has gone missing at some point in the past. The lists I found online only go back to 1985, but the system capacity seems to vary quite a bit in the years afterwards. I'm not comfortable using the 1985 amount.

Dougflas on Mon July 14, 2014 9:55 AM User is offline

If it were mine, I'd replace the compressor and accumnulator, use new hoses, (AMA can rebuild your old hoses), flush the system, and keep it R12. If you have a EPA ticket, you can buy r12. In fact, I have at least 3 or 4 30lb canisters of it.

bohica2xo on Mon July 14, 2014 10:32 AM User is offline

That vehicle was, and still is popular. That means parts are easier to get.

AMA actually has the hose set on the shelf:
Compressor manifold & hoses

If the leak never showed up with dye, and you put a dozen cans of Freeze12 through it I would check the evaporator drain. Us a long cotton swab or a pipe cleaner. With that much product through it, there should be some oil & dye in the drain if the evaporator is leaking.

I would replace the engine fan clutch. Use the HD thermal clutch. GM was trying to squeeze economy and put non-clutch viscous drives in some of those cars. The warranty on a new Delco replacement clutch is only 12/12 - they wear out. If you have a 3 year old clutch and paid 30 bucks for it - replace it.

1) Find and fix the leak.

2) Clean the system. Back to bare metal inside the condenser & evaporator.

3) Replace the compressor.

That should take you back to OEM performance, if you use the OEM R12 refrigerant.

"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Jonathan on Mon July 14, 2014 11:56 AM User is offlineView users profile

Thank you for your replies. I do have a EPA 609 certification, so I'd like to try and purchase some R12. Dougflas, are you interested in selling any of your R12?

I've been pricing flush equipment - it seems to almost be cheaper to buy a new evaporator and condenser than to buy a decent flush kit, although a flush kit would pay off over the course of several vehicles.

I had the drain checked from the evaporator. No dye showed up there. Is there a life span for the dye? Will it not show up under a UV light after a few years?

The fan clutch is about 7 years old. I replaced it when I put a new engine in (350 in place of the stock 267) a while back. Not too many miles, but it's cheap insurance to be sure everything is working correctly. When I replaced the engine, I used an underdrive pulley. I was able to get decent cooling out of the car afterwards, but would you recommend reinstalling the stock pulley to turn the compressor back up to factory spec?

Dougflas on Mon July 14, 2014 12:33 PM User is offline

Yes, I'll sell a drum. Let me contact Tim and see if it's ok.

Ok, Tim says ok to sell some. Pls contact me directly com aol. @ dktv just reverse the addy

Edited: Mon July 14, 2014 at 12:40 PM by Dougflas

bohica2xo on Mon July 14, 2014 12:53 PM User is offline


The UV dye is pretty persistent. But if you are Ok with a total system replacement, then it is a non-issue.

Too often here on the board we see people that want to do the bare minimum, and I tend to answer in that direction. Staying with R12, and a TSR should be a great fix.

"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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