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Discussion Starter · #1 ·
I have a 2003 s-10 2.2 litter with a slow ac leak. Ac hasn’t worked for years, finally had time to work on it, replaced accumulator and the two hoses from the compressor, got all mixed up on o ring sizes, crushed a few of them and wouldn’t hold vacuum. Finally think I got the correct sizes because it held a vacuum for 24hrs. Charged system, went on vacation for a week and came back all was good, still cold and compressor was turning on. Drove for a week and system was slowly loosing Freon because it was getting warmer and warmer now must be all gone because compressor won’t turn on.

Put gasket between hose and compressor where last shop had put o rings. Is there a diagram that shows o ring sizes to make sure I got the correct sizes?

Also only place I can’t see is evaporator but it’s a pain to get too. Is it possible it’s leaking from compressor clutch or somewhere on compressor and I just can’t see it? It’s strange it held vacuum and Freon while not in use but leaks when using. Any thoughts?
 

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Guessing it's the original compressor. check the case in the middle...liked to leak there. When you recharge, put some dye in it...makes leaks easier to find.
 

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Discussion Starter · #3 ·
Yes original compressor. Sounds good will do in a couple days when free. I put the oil with dye in it when I replaced the accumulator but I’ll try the Freon with dye.
 

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Sometimes you need a black light flashlight to see the dye. Especially slow leaks. Ebay has them relatively cheap. Any 365 Nm flashlight will work.

Unfortunately O-ring leaks that don't show with vacuum can occur with the high pressure in an A/C system. You really need to pressure test the system before re-charging. It pushes on the o-ring rather than pulling.

One of these seal kits might be of use to you:
 

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Discussion Starter · #5 ·
Yeah I have one of those o ring kits already. Just never know if I need the thick or the thin ones on a few connections and how tight the rings should be. And the o ring fits over the male end and should slide inside the female end?

I can’t find a diagram that shows what size o rings should be on which connectors.

Also how do I pressure up the system?
 

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Some of the better A/C capable shops have a Mastercool 53010-AUT - Nitrogen Pressure Testing Regulator Kit (R12 & R134A) that they run before vacuuming. I believe they use nitrogen for the pressure to avoid introducing any moisture. I hear Argon from a mig welder would also work. Argon is totally inert.
The instructions with the kit call for 250-300 psi. That might be fine for a new system, but most shops limit the pressure to 150psi on older vehicles. That's high enough to show any leak.
Trick I suppose is finding who in your area has one. Or buy your own. They're right around $150.
Picking the right o-ring I guess is a learned skill. I usually look for the one in the kit that appears closest to each as I take them off. If they've been juggled a few times that can get tricky. The ones on the compressor to hose fitting are sometimes one thick one and one thin one. GM played musical chairs with the length of that adapter. Some were equal length, some weren't. I put a little synthetic grease (SuperLube) on each o-ring to prevent rolling. It won't hurt the rubber.
 
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