AC leak can't find!

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Ok, so I just flat screwed up on this one. I was replacing my radiator on my '99 LX470. When I was pulling it out I obviously got it caught or banged it on something, because All of a sudden a big old hiss from the front area. It was pretty loud, so I felt it best to vacate the area until it stopped. Pretty clearly it was an AC line or something, cuz nothing else has that sort of pressure. I went ahead and got the radiator done so I could go buy some AC dye and find the leak, however now I can't find it even with the dye. I can hear it hissing immediately when I put more in, but the dye is not showing up anywhere. It's either right at the front at the condenser or one of those lines right around the radiator. Do you have any idea where it could be coming where the dye wouldn't be seen? Of course I'm heading on a road trip at the end of the week so if I can't figure this out by the end of the day, it's going to the shop and big bucks coming my way I'll bet. Anyway any advice would be super appreciated!
 
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Have you tried a UV light to try and locate the dye? Rather than needing to refill the system and have it all leak out as it sounds like you have a significant opening in the systwn, I would recommend pressurizing the system with at least 250 psi of nitrogen. If you don’t have a nitrogen tank I would try clean dry compressed air. If you don’t hear the leak, you would need to spray a soapy water mix on the lines and look for bubbles.
 
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Thanks, yeah I have a uv light and am surprised I cannot see anything spraying out since it's so forceful. I thought it would be clear as day.
 

flintknapper

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Ok, so I just flat screwed up on this one. I was replacing my radiator on my '99 LX470. When I was pulling it out I obviously got it caught or banged it on something, because All of a sudden a big old hiss from the front area. It was pretty loud, so I felt it best to vacate the area until it stopped. Pretty clearly it was an AC line or something, cuz nothing else has that sort of pressure. I went ahead and got the radiator done so I could go buy some AC dye and find the leak, however now I can't find it even with the dye. I can hear it hissing immediately when I put more in, but the dye is not showing up anywhere. It's either right at the front at the condenser or one of those lines right around the radiator. Do you have any idea where it could be coming where the dye wouldn't be seen? Of course I'm heading on a road trip at the end of the week so if I can't figure this out by the end of the day, it's going to the shop and big bucks coming my way I'll bet. Anyway any advice would be super appreciated!

Most likely scenario would be one of the lines. Especially if you are in a rust belt area or where they salt the roads. Any of the lines can corrode and develop pin holes, cracks or worse. If 'bumped' might be enough to damage one.

Since the leak is not readily visible look in areas where lines pass through supports, join the condenser or are insulated with material.
 
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Crap, well I guess it's the condenser. Found it by hanging a paper towel down between the radiator and the condenser, then see a nice little green dot. I'll look around here for a how-to on that, and decide if I think it's something I can tackle before I leave on Friday. Unless somebody has a really super cool link before I find it myself?
IMG_20210726_161950.jpg
 

flintknapper

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Crap, well I guess it's the condenser. Found it by hanging a paper towel down between the radiator and the condenser, then see a nice little green dot. I'll look around here for a how-to on that, and decide if I think it's something I can tackle before I leave on Friday. Unless somebody has a really super cool link before I find it myself?View attachment 2742425

You found it, good work.

New condenser comes with the drier attached and a new desiccant bag installed, so the replacement is pretty straight forward. You'll need to use new Orings anywhere fittings are involved. Also add a couple of ounces of PAG46 refrigerant oil to the new condenser.

The system would then need to have a deep vacuum pulled on it.....to check for leaks and remove any moisture before weighing in a charge of refrigerant. IF you do not have the equipment....then replacing the condenser and taking the vehicle to a reputable shop for charging would save some money on labor, BUT some shops will NOT guarantee the work if they didn't install the part(s

I believe your year model also has a condenser fan....so check that for proper operation *apply 12vdc directly to it while it is removed*.
 

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