Continuing A/C leak diagnosis

[Lee in Mountain View]

Board members,

I’m getting back to diagnosing my A/C leak problems. On previous posts I mentioned that my system was completely empty of refrigerant, I had it charged, only to have it leak out in short order. So, I’ve visually inspected most of my system, still have to check the rear A/C components, and used a UV light and here is a pic of the rear of my compressor. I’m thinking this is a strong indication of a leak at this location. Just wanted to get your thoughts. Have not found any other leak indications using the UV light. I took of my front grill and cleaned and inspected the condenser as well.

Thanks for your comments.

[sfeaver]

Thats not a leak, thats GMs way of checking that it was tightened before it left the factory. Of course, if thats the original compressor. They generally leak on the bottom side, you will see oil and the green dye.

Another spot to check is the drain from the evaporator box,

[Onthewater01]

I had the same issue, it was my rear a/c line. They like to corrode around the frame mounting clips.

[nico541]

If you have rear AC the common spot for it to leak is in the rear AC hose on the edge of the floor of the dog house. Thats where I found mine. I cut some old garden hose to cover the new line and made a quick and dirty bracket to hopefully prevent any rubbing in the first place.

[Lee in Mountain View]

Thanks for the responses! I have the dog house off and will check that location and will check the various rear A/C connections as well! Not done yet!!

[Lee in Mountain View]

So, I guess I should ask, what does an A/C refrigerant leak look like when using a UV light to find it?? Does it look like a spray or a drip?

The back side of my compressor has a fair amount of UV dye that looks as though it was spattered about. Do you think i found my leak location?

Thanks

[nico541]

Did you run some refrigerant with dye through it? You can either buy a little refrigerant can pre-mixed with dye or buy the dye separately. But you need to run some dye/refrigerant through your system for it to show up. It will show up as neon green. I bought the dye separately and just poured some into the hose of AC manifold kit I rented for free some Oreily's before I put some registrant in it. I have a pic where you kinda see the leak I found

[albrow100]

I’ll 2nd the leak at the rear a/c like near the rear of the dog house opening
Mine rubbed through there and I replaced the Line assembly adding padding to hopefully prevent it from happening again

[Astro Pop]

If your system is still empty you can try using a standard compressor to pressurize the system and listen for air leaks. Simple, effective plus cheaper than R-134. Take it up to about 30 - 40 psi. Downside is that you need to vacuum the crap out of it once it's fixed. Like about 2+ hours on a hot day.

[MechBob]

UV does not really seem to work well,like it did in old R12 systems.As said before,I generally try air pressure, but, in the case of my last issue, would take 16-24 hours to leak down, so impossible to find with air.Was my summer(96) van. Took to friends shop,filled it, checked with his latest expensive leak checker,found nothing.Came home and got my old TIF leak checker, new batteries,slight leak bottom of the compressor.Seems like the newer testers just are not as sensitive.Anyway,looking under compressor,and looking at it after removal, no UV dye stains, no oil stains.Replaced comp. has been fine since then.But, as most know, the o rings in the compressor are a known problem, has the housings move around.Replacement compressors are pinned.

[Onthewater01]

I used the oil with dye added. I saw it dripping from the line at the location of the leak, and also saw drips on the garage floor. I didn't even have to use the UV light!

[Lee in Mountain View]

Yes, when i last had it charged, they put in the chartreuse dye. I’ve been checking all the lines and connections with the exception of the rear a/c, thats next. All of the connections in the engine area I’ve check thoroughly with the uv light. Still have to crawl under the van and check the connections under there that lead to the rear a/c. Thanks for all the comments and suggestions. I’m really trying not to just start changing out parts.

Lee in Mountain View

[Bat]

If your system is still empty you can try using a standard compressor to pressurize the system and listen for air leaks. Simple, effective plus cheaper than R-134. Take it up to about 30 - 40 psi. Downside is that you need to vacuum the crap out of it once it's fixed. Like about 2+ hours on a hot day.

Hi,
I was taught to use nitrogen to pressure test as compresed air mixed with the oil and traces of refrigerant can explode...
Cheers

[Sailing_Faith]

Check this one...
https://www.astrosafari.com/viewtopic.php?f=34&t=140264

[Leeann_93]

I was taught to use nitrogen to pressure test as compressed air mixed with the oil and traces of refrigerant can explode...
Cheers

Nitrogen is great to pressure test because it doesn't add moisture into the system. Compressed air does. Moisture will cause the refrigerant to crack and turn back into acid, which you definitely don't want.

[Onthewater01]

Pro A/C techs use nitrogen to test new systems without refrigerant. You need the Nitrogen bottle, gauges and fittings which most of us don't have. The dye worked well for me when added to my system for troubleshooting before evacuating it when there was still some refrigerant left in the system. Running the compressor forces the dye out at the leak site. With Nitrogen, you need a clean system and you have to spray on soapy water at every connection and look for bubbles. If there is a leak in a line or at an unlikely location, you may not find it.