Automotive Air Conditioning Information Forum

Hello everyone!
I apologize this will be a long story!

I'll try to be clear, concise and and do my best to go in order.
I work for a tier one supplier so I have access to an actual AC machine. Please understand we do not do AC work so if I did something incorrectly, I apologize in advance! We have the machine for when we tear down vehicles.

2 years ago my original compressor clutch died as well as the bearing.
Found a good clean running compressor with 55k miles on it.
Might be my mistake, maybe not. We'll see.

So I took it to a shop (before my current job) had all the refrigerant recovered out.
Took it home and changed the compressor, dryer, expansion valve and every O-ring in between, including to the condenser.
Went back to the shop. Said it held vacuum for 45min filled it and away I went.

Fast forward to this spring. It wasn't as cold and definitely had leaked down. I needed a new radiator and in order to do that I pulled the condenser.
Now I'm at my current job with the machine.
We pulled a 32psi vacuum and it held again for 40-45min.
Filled it with 1.5lbs of refrigerant and I thought I was all good.
2 days later, warm.

We recovered about half the refrigerant we put in.

It was suggested that since my radiator was bad, should probably change the condenser, which I'm sure wasn't at 100%
So I do that.
We pull a vacuum. 31-32psi 30min.
Go to fill it and it has a massive leak at the condenser fitting. There's a void at the surface where the o-ring sits. (odd it didn't show on the vacuum)

OK...So I exchange that. New one looks good.
Install it.

Pull a vacuum-31-32psi again. 20min pass..fill it. Takes the refrigerant. Ice cold!

36 hours later...warm again. Now I'm getting

So talking to a few of my good parts guys and just all around smart guys, it was suggested that the schrader valve(s) are leaking. That won't show a vacuum leak but will leak after lines are removed.
Good suggestion! and at a 1.00, worth it!
I also noticed that the low side cap was wet. Good indication it was leaking there.
I did NOT change the high side one as that was new with the dryer, and cap was dry.

Go to pull a vacuum. Fails. 3 times. (I took the lines off and re set them just to check.)

Now I'm really irritated. Every vacuum test passed with ease until now.

So a co-worker brought in a line set to connect to a cylinder here and I pressurized the system to 225psi. Closed the cylinder so it wouldn't keep feeding the system. And I proceeded to spray every fitting and hose crimp with soapy water. Including the high side schrader valve. NOT ONE BUBBLE.
I get a piece of vacuum hose to listen everywhere, including the vents in the car and shoved the hose under the dash from the passenger side. Not even a hint of hissing. From anything.
I checked every line the whole length. The good thing is, everything has been washed now!
So this took me 30-35 min. Went back to the cylinder line gauge, and it didn't drop one bit!!!

So in the meantime I had ordered next day a Halogen Gas AC Freon Refrigerant Leak Detector not an expensive one by any means, but good reviews and if the leak is that bad it should show!

So I decide, ok lets try to pull another vacuum. Just to see.

It pulls 32psi but this time doesn't "technically" fail according to the machines algorithm, but the needle was slowly dropping. 1psi over 30min. I KNOW it's leaking but the shop manager told me fill it anyway, and check with your leak detector when you get home.

I get home, leak detector comes. I start to sniff around. First thing I go to remove, high side cap, and it's pressurized! It was actually leaking from that schrader valve.
Odd that didn't show up doing the 225psi test.

However, I'm not convinced that is my only source of a leak. That will not show a leak under vacuum so there has to be another leak, somewhere.
The high side valve eventually seated, still unsure why it was leaking, and I proceeded to check every fitting in the system, again.
Nothing, not one sign of a leak.

I did check the low side valve and gave it a quick "blip" to make sure there was still refrigerant in it, and there was as the detector went nuts.

But maybe the pressures were too low now to force passed any seals at this point.

OK pretty much the end of the story.
So now I have a leak that will hold 225psi but won't hold at 175psi (my understanding of where the system runs at on the high side) and won't hold vacuum now either.

I'm about to take it in to have it diagnosed. Any thoughts, tips, suggestions would be greatly appreciated.
My personality is, once I'm in it, I have to figure it out.

Thank you for reading all this! Hope it made sense.

You are trying to leak test- based on the assumption it leaks constantly! Leaks can be like farts- intermittent. So that is why I use the dye- it does not care when it leaks- but will show you where it leaked- works great. You can buy it and the UV light at your local discount auto store.

I forgot to mention, I used a red dye a week ago. I don't see any indication anywhere from it.

Which makes me lean on evap.
Is there anyway to test the evap while it's in the car?

First, you can not pull a vacuum to 31 to 32 PSI. 29.9 is all she writes. Red dye is useless; use UV dye with the light and glasses. You can check the evap at the drain hose just be careful not to get condensation into the detector tip. You can try to place a shower cap or plastic bag around the compressor over night and shove the detector tip into it after 10 hours or so. Some leaks are present under vacuum, some under pressure, some on the compressor shaft seal depending upon the position of the shaft. Do your sniffing in a garage away from drafts.

Doug, while you're right that the meter only reads up to...well 30, the needle went past it every time, the first few times it sat there, showing no leak at all. Clearly I'm only guessing at the 31-32. But it's certainly farther "north" than 30psi.

Anyway.
Interesting on the red dye. Good tip. I'll try the UV stuff.
Really good tip on covering the compressor in a bag! That's slick.

Thank you!
It might not be until next week until I get to mess around with it again. But I will definitely check these.

Laws of physics dictate that vacuum cannot be 31-32. Your gauge is a little off.

AH ok! I'm slow.
Thank you.

Vacuum is the absence of atmospheric pressure- so it can only be that with no atmospheric pressure- it can vary based on sea level...as does the atmospheric pressure

Does anyone have a link to where I can buy a rebuilt O-ring and seal kit for this compressor?

Also, can anyone help me determine the difference between two different compressor numbers I have found?

Rock Auto shows a 10SRE18C from GPD manufacture and a 10SRE20C from 4 Seasons.

Well. Broke down and took it in to the shop yesterday.
45$ to tell me where it's leaking.

LOL if anyone is still paying attention, I'll let ya know.