# A/C Leak



## mwysienski (Apr 5, 2011)

Hey yall,

Can anybody help me with this a/c leak I've acquired? My air stopped working about a week ago. I bought a can of R134a with the uv dye. I put it in with the car running and a/c blasting. The temp from vents never dropped. The pressure on the gauge never went up. So it seems like it just went in one hole and out another. The problem is I don't see any dye on any of the lines or fittings. The condenser looks fine...

There were a couple places I seen where some mentioned an O-ring that commonly goes bad. Where is this problem O-ring? That'd be sweet if that was the only thing I needed to buy. Well, aside from the dryer (which from what I hear is a must to swap when the system has opened for an extended period of time).

I bought the manifold gauge set and a vacuum from harbour freight, but I'm kinda at a loss as to where to start. I could get a pressure reading with the air on and off, but I wouldn't really know what to do with that info....

There IS dye all around the low pressure fill fitting by the expansion valve (I think that's what it's called...where the a/c lines go through the firewall), but I think this is just from over spray taking the bottle on and off the line. Something I thought was a little weird was when I took off the refill bottle and looked quickly at the fitting, it kinda looked like there was little air bubbles coming up through a little puddle of dye sitting inside the fitting. So that makes me wonder if the little pin in there has lost its grip on holding the pressure in the system. That's an expensive hose though. So I don't want to just buy one and see what happens.

I was thinking of pulling a vacuum on the whole thing and getting something to spray around the suspected areas to see if that uncovers the mystery of the leak. Is there something special I should use for that? I'm guessing water is not good right? You don't want water in there...? When pulling a vacuum, you use the low side right? ...with the car off?


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## Anony00GT (Mar 6, 2002)

You got the gauge set, now use it :beer:

Start by posting pressure readings, high and low, with the A/C off first and then with it running.


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## mwysienski (Apr 5, 2011)

After spending some more time looking at all the a/c stuff, I think it's actually the low pressure port that is leaking. When I took off the dust cap to put the gauge on there, it made a hiss sound...like I just opened a bottle of soda. So that's a pretty big indicator right there...I think.

Nevertheless, here's my readings with air temp of 74°F:

Car Off
Low: +31.5
High: +31.5

Car On
Only Low Open: +13.5-16
Only High Open: +37-38.5
Both Open-Low: +21-22
Both Open-High: +22-23

The dash is to indicate the range that the needle was fluctuating. It slowly bounced up and down in a repetitive motion. I don't think having both gauges open at the same time is really worth anything because it just gives another passage for the freon to travel from high to low without taking the proper path...right? And I know I should've had a thermometer handy, but I didn't. I just took the air temp from my weather app on my phone. I'll have to get a thermometer for when I finalize everything.

The gauge seemed to work great. Opening the high valve would bring in freon to the sight glass. After closing the high valve, opening the low valve would drop the pressure, and I could watch the freon boil off behind the sight glass. So it seems to me that there just isn't enough freon in there.

If it is the little ball in the low pressure port that is not holding tight, is there a little female-on-bottom-male-on-top adapter that I could screw on there to give it a new little ball thing. I guess it's probably called a pin (not a little ball thing). I don't see one online. I'll check Harbour Freight for something to try out. 

Whether or not that adapter fix is possible, do I need to drain the system and get a new dryer if it never completely drained? Can I assume that the presence of freon negates the presence of air in the system?...at those pressures?


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## Anony00GT (Mar 6, 2002)

You should be watching with both couplers (on the car) open and the valves closed. Only open the valves when using the yellow hose (vacuum pump, fill, etc). The valve connects the manifold to the yellow hose.

Your refrigerant level is way low.

Fix the leaky valve, pull a vacuum on the system, then fill with R-134.


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## mwysienski (Apr 5, 2011)

...what's a coupler? lol. The things I called the low and high pressure ports?

Are you sure I need to keep the valves on the gauges closed? I don't think that the pressure will reach the gauge this way.

I understand the "fix it, vacuum it, fill it" process. It's the "how" that I'm looking for some help with. Has anyone seen something similar to this hypothetical adapter I described? I'm hoping that will save me having to replace the whole line that goes from the expansion valve to the compressor. And that's only if its the pin that is the problem...if it happens to be cracked where it meets the hard line...well I guess it would be toast.

What about my dryer...? Is there a way to test it...or you just gotta go on whether or not you think it's been in contact with the atmosphere?

Oh, and is the low port the correct place to draw a vacuum from?


...sorry, I got a lot of questions.


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## Anony00GT (Mar 6, 2002)

You need to pick up an A/C service manual.

The coupler is the part of the gauge set that connects to the car, has a little valve on it. Those need to be opened. That will connect the car to the gauge. The valve on the manifold itself connects the respective hose (high and/or low) to the center yellow hose.

As for the fitting, IIRC it's the kind that looks like it has a little black ball in it, if that's the case, the line has to be replaced. If it looks like a tire valve, the valve core can be replaced using a tire valve core tool, auto parts stores sell A/C valves for those, take the old one to the store and match it up.

As for the dryer, technically it's supposed to be replaced any time the system is opened. If the system is only briefly opened though (like changing a valve core), just run the vacuum pump a little longer and leave the dryer in place.

Draw vacuum from both ports. Yellow hose to vacuum pump, both valves open, pump on. When done, close valves then shut off vacuum pump. System should hold vacuum.


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## mwysienski (Apr 5, 2011)

My gauge doesn't have a coupler then...

http://www.harborfreight.com/a-c-manifold-gauge-set-92649.html

In the manual it clearly states that when using just for a pressure reading, the yellow hose has to be placed on both ends of the T-fitting to create a closed loop. So that means I can only watch the pressure of 1 side at a time.

So I guess when filling I'd just shut off the high side and pump that stuff through the yellow, into the manifold, then through the blue side to the a/c line... And drawing vacuum would be the same just do one side, close that side, then do the other side.

Yea, it's the little black ball one...IIRC...got it! Thanks! Doesn't everybody have the same one? ...at least with our cars?

Well it looks like I'm gunna need a new one of these:
http://www.ecstuning.com/Volkswagen-Jetta_III--2.0/Climate_Control/Air_Conditioning/ES261716/
And it's prob best to just get one of these too:
http://www.ecstuning.com/Volkswagen-Jetta_III--2.0/Climate_Control/Air_Conditioning/ES261715/

What about gaskets or O-rings? Or maybe some special lube that I don't know about when putting them together...? When I take that hose off the compressor, doesn't it loosen the other hose at the same time? Does that cause a problem for that O-ring?


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## Anony00GT (Mar 6, 2002)

Never heard of looping the yellow hose. Both valves closed on the manifold, couplers connected and open, you'll get pressure readings. Yellow hose is irrelevant for a simple pressure reading.

The coupler is the part that's at the end of the hose, the piece that connects to the car. Trust me, you have two of them. This is a coupler:










With both valves closed, you can get a pressure reading. The valves on the manifold open it up to the center (yellow) hose for evacuation, vacuum, and recharge purposes. This video explains it very well:


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