Ok, so I guess after lucking out on both my 98 and 2003 with neither ever having the infamous rear a/c leak (both of which I still own), it's only fitting that my 2012 would now develop the problem.

It's definitely leaking from just above the rear expansion block where it comes through the floor (as seen from underneath the van). One question is, does the 2012 use the extension tubes or do the evap lines go right into the top side of the expansion block? I'm debating whether I want to bother trying to just replace the o-rings on both sides of the block or just replace the evaporator. I was going to remove the block to see what was going on but couldn't get the dang lines to come out of the bottom of the expansion block after removing the nut. The retainer piece wouldn't budge. I'm either missing something or they are just plain stuck.

Has anyone dealt with this issue again on the newer vans? I thought this problem was resolved from previous generations but I haven't been able to find much on this with the 2012's to know if it's a common issue again or what. Hopefully it's just an o-ring issue but I'm just looking for some insight before I fully tear into it.

Thanks

 

I just seen this sorry but I really can't help you. Maybe you can help me. I have a leak and was wondering how you found yours. Does the system come with dye in it? Did you use a leak detector. Any info would help.

 

No problem. Yes, there is a dye in the system from the factory but my leak was pretty obvious. I had refrigeration oil leaking from under the right rear lines where they go up into the rear evaporator from under the van. I used an electronic leak detector to verify leak and to test my repair but never needed to use a light to detect the dye since it was so obvious. You also can also use a leak reactant solution that will make bubbles in the presence of a pressure leak. This can be either sprayed or dabbed on with a small brush. I find the bubble solutions work very well but don't use just a soap and water mix. Soap and water mix works fine for gas lines but for a/c systems, you need the real stuff because it is designed for small refrigerant leaks...The smaller the leak, the bigger the bubbles.

In my case, I use this van for my business and I had installed custom built racking and a floor that would have to be removed to access the rear evap. Since I don't use the rear air anyway and I'll rag this van out before I ever get rid of it, it wasn't a big concern for me to do the "quick fix" of just cutting the lines (basically right behind the right rear tire, removed tire for more room) and capping them off. To cap off, after cutting the lines (with a tubing cutter) I installed two appropriately sized brass flare nuts on the lines and used a flaring tool to flare the ends of the lines and then capped both lines off with a brass flare cap. Then replaced the filter/drier, evacuated and recharged the system. Worked great and has no leaks ever since. Some will claim you can't mix brass and aluminum because it will corrode but I've never had a problem with it. Did a similar repair with a brass coupler where a/c line got smashed under the hood and never had a problem for the thirteen years I had that particular car.

I am assuming you have rear a/c? This rear leak was a big problem on older Caravans and there is a bypass kit available for them that is basically a u-shaped piece of tubing that couples the lines together under the the vehicle. This kit was not relevant to the 2012, at least not last year anyway so I just did it "my" way. DISCLAIMER: I'm not advising that you start cutting into your a/c system. I'm just telling you how I "fixed" mine.

As far as finding a leak, look for obvious signs of oil around fittings or use a fluorescent light to look for dye. If you've got that tell-tale oily residue on the lines coming down from the rear evaporator for example, you've probably got a leak. If you have access to an electronic leak detector, go slow and keep airflow to a minimum else it can blow the leaking refrigerant away from the detector nozzle. Air blowing on the sensor can also set it off as can a water drip, so don't get fooled. Verify with light or bubble test. If you can access the rear evap, remove the panel and check the evap itself as well as the lines from underneath. Check all line connections front to back and where lines enter and exit firewalls and panels, etc.

You can also have a leak in the front evaporator (very difficult to access) or in the condenser. Also, sometimes a/c compressors will leak from the shaft seal between the clutch and compressor body, or will only leak there during colder months, like over the winter. If this happens, it's hard to detect because I've also seen very tiny leaks in an evaporator that will act the same way so it's hard to diagnose unless you can get confirmation with a detector or dye. If the system holds a charge except over the winter, it may be easier/cheaper just to recharge it than to tear your entire dashboard apart.

Sometimes you can get a high pressure leak somewhere on the high side that will only leak when the a/c system is on (approx pressure 175-250psi when running) so if the car is off, you might not detect it. Conversely, you can have a leak on the low pressure side (approx 25-40psi when running) that only leaks under higher ambient pressure when the system is off. In other words, when the system is off, pressure equalizes on both sides of the system, usually to around 70-100 psi on both sides depending on ambient temperatures. When the system is running, the high side can get as high as 250psi or more, and the low side will drop to around 25-40psi or so. A leak might be very tiny or quite large depending on where it is and/or what the pressure is. That's why using the light to detect the dye or a bubble test can be useful if you suspect an area but nothing is picked up on the detector.

Not sure if any of this helps you but good luck.

 

Thank You amanaman1 Your explanation was outstanding. You have given me many ideas and things to do. Weather to fix or to plug. I really appreciate that.