How do i determine why i have a refrigerant leak

1998 GMC JIMMY
125,708 MILES • 6 CYL • AUTOMATIC
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ROYCAR71
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I took my vehicle back to mechanic for evacuate and recharge after installing a/c conponents and doing a/c flush. He told me "I have leak in 2 places, between evaporator outlet to accumulator and compressor hose assembly area. The area where evaporator is, I know now i could of did more. What would be a good lubricant to add to make it looser to screw all the way on? I did add an o-ring that wasn't there before too. Maybe I need to remove it. As for the compressor hose assembly, there are 2 o-rings on hoses, but i might be missing a seal or something needed on top of compressor? Thanks advance.
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May 29, 2012 at 3:59 AM
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PROMECHANIC
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You don't need lubricant. If it is that tight but still leaks you probably have it cross threaded. It should screw on easily. If it needs lube, there is something wrong. Don't add any o-rings. If there wasn't one there before then don't add one.

For the compressor leak, the two o-rings are the only seal there is and the only one that is needed. You need to put refrigerant lube on the o-rings then tighten the bolt.
May 29, 2012 at 4:58 AM
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ROYCAR71
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It took me over 2 hrs initial to unscrew evaporator from accumulator. I used a lot W40 and b blaster. I noticed a lot of black dirt or something stuck threads. Before I put back on I tried to scrub threads with wire brush with W40 to take some that stuff off, I guess I didn't do a good job. Is there a cleaner that can help remove dirt on threads?
May 29, 2012 at 5:44 AM
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WRENCHTECH
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The threads don't do the sealing/ they merely pull the 2 pipes together so the O-ring can seal. The accumulator uses an O-ring and the connection at the compressor uses special rubber washers.
If you damaged the threads on the accumulator when working there, you will likely be replacing and evaporator now.
May 29, 2012 at 10:09 AM
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ROYCAR71
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Before installing new accumulator. There wasn't o-ring on tube going into accumulator from evaporator. There was one on accumulator to compressor. As for the compressor, I have 2 or 3 types that came with it. I just used the o rings on tube. How do I know which washers to use for compressor.
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May 30, 2012 at 10:16 AM
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WRENCHTECH
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You use the ones that fit the hose.
May 30, 2012 at 2:51 PM
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ROYCAR71
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there is a inlet tube with screw nut that goes into the accumulator. It seems I have it as tight as I can get it. Is that screw nut suppose to move back and forth on tube?
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Jun 1, 2012 at 11:19 PM
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WRENCHTECH
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Definitely not. You have probably cross threaded it and now you'll be replacing the evaporator. I warned you a few times that you shouldn't be tackling this job because it will cost you more to learn the hard way.
Jun 1, 2012 at 11:25 PM
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ROYCAR71
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I am not talking about screw into accumulator. It is the screw nut on tube. It slides back in forth. but connection that screws into accumulator is tight.
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Jun 1, 2012 at 11:32 PM
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ROYCAR71
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It appeared to be like this when i took it off. It now more loose since i use some wd40.
Jun 1, 2012 at 11:38 PM
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WRENCHTECH
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If it's loose in any way it will not hold refrigerant and there is no way to repair the threads except replace the component.
Jun 1, 2012 at 11:43 PM
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ROYCAR71
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I understand that. The threads are fine and nice and tight. My concern now is it typical for bolt that screws in to accumulator that is over evaporator tube to slightly move back in forth? Thanks for you patience.
Jun 1, 2012 at 11:48 PM
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WRENCHTECH
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If that nut got tight but still moves on the pipe, then it is not fully seated and the threads are trashed and so is the evaporator.
Jun 1, 2012 at 11:56 PM
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ROYCAR71
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Hmm, is was like that when i took it off. I just used some WD40 to break nut off accumulator. Thanks.
Jun 2, 2012 at 12:02 AM
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ROYCAR71
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I don't mean to be a ball breaker. But I have post another pic of evaporator the display what I am saying. Do you see how screw end slid down on inlet? That is what I am saying. Thanks.
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Jun 2, 2012 at 12:10 AM