ac leak only in winter?

**michael redmon** · 08-01-2016

I have a slow freon leak in my 02 gp. I have to fill it up at the beginning of every summer with the cans. I have access to one of those automated freon machines. I put a vacuum on it for 30 minutes and it didn't bleed down. I have soaped fittings, put dye in it and can't see anything. Could it be a leak at a fitting that only occurs in the winter? Any suggestions would be appreciated because I lose access to the freon machine later this year (I am changing jobs). No, I am not a mechanic...not even close.

Thanks!

**J57ltr** · 08-01-2016

This is pretty common on all cars I've worked on. The leak is so slow that you will never see it in 30 minutes. You will need days, to see anything significant. The leak is just so small that it takes several months to get to a level where you need to add some. Next time put a can with dye in it, then look for it next summer. I have had cars that only took a can a year. If it's that low I don't even bother with fixing it. My wife's 96' Lumina would leak enough that I put a can in around March and again around October. We run AC nearly year around here. We had that car for about 4 years and I never did anything else to it AC wise.

**mguzzo** · 08-01-2016

maybe the leak is in the eval core inside the car under the dash.
Agree that you need dye injection into the system and a black light. that **** will light up like a crime scene.

**FordMan77** · 08-02-2016

Check the condenser after you added dye? They can have a pinhole in them and only show up with the UV stuff and take forever to let the system leak down. Other than that maybe the compressor? Hopefully it's not the evap coil. How long after you vac'd it did you let it sit with the vacuum on it? It is recommended do a min of 30 min vac and then another 30 min of sitting.

**michael redmon** · 08-02-2016

I am going to recheck everything plus actually check the evil core under the dash (I forgot about that)
Thanks again

**nik12937** · 08-02-2016

If the evaporator is leaking you can usually see the dye in the drain tube. Stick some pipe cleaner up the tube and pull it out, see if it glows in UV light. With such a slow leak it may take a few tries with the dye.

**scha0786** · 08-04-2016

doubt its your evap coil but yes that is the way you find that leak, look in the drain tube for the dye because it will show up.

Another spot to check is the low and high side service ports, these can leak. I think you can replace these but don't take my word. Otherwise just replace the whole line set as they are cheap.

One more spot to look is around the compressor housing, mine was leaking there. This one can be tricky to find because as the compressor gets hot it actually hides the dye but under careful inspection and black light you will see it.

One more thing you can do is vac your system down and fill it with nitrogen to 100 psi and soap all the joints or listen for a hiss. This is what I typically do.

Final option is to buy a refrigerant sniffer and these will almost always find your leak or get you in the area.

good luck, worst case just replace the whole dang thing (condensor, line set, drier and compressor) all the parts is only like $500 and is all labor to get in and out.

**michael redmon** · 10-03-2016

Found the leak. High side port.

**J57ltr** · 10-03-2016

That's exactly where my wife's old car leaked. I never even bothered to fix it.

**JamesIvey24** · 10-03-2016

take the cap off the port....make sure it's not pressing the core down..aka..too damn tight

**michael redmon** · 10-04-2016

Guys, I need some guidance. Is this what I need to change hi side port?

-ACDelco 15-5438 GM Original Equipment Air Conditioning Service Valve
-special socket
-anything else????

Evacuate freon, take off port with socket, screw in new port, fill with freon. Done.?

I want to fix it because I lose access to the AC machine at work soon.

**rickisrad** · 10-04-2016

yes, auto parts store also have them. I got mine from autozone. No special tools needed. one wrench to hold the line from twisting and one wrench to get the fitting off. Don't over tighten, just snug.

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