Rear Ford Factory AC Leaking

[joefromsf]

Van is a 2012 E350 RB XLT Wagon, Agile 4x4, SMB penthouse and basic home-built interior. It has factory AC in the front and rear of the van.

At some point on our 10-week cross country trip last fall the air conditioner stopped blowing cold air. The air was cooler than ambient air but not cold. Due to the time of year we were able to survive without much discomfort and didn't have it looked at over the winter.

Brought it into my Ford Dealer to have it checked out yesterday. They said it passed a pressure test so they recharged the system, and said it blows cold air again. I drove it home (10 miles) and ran the front and rear AC and felt it blowing cold air myself. Parked the van in the garage and when I walked by a few hours later I noticed some bright green fluid under the rear of the van on the drivers side where the rear AC is located.













I assume that's a drain hole, probably from a drain pan under the rear AC, correct? I know there is a fan and motor back there for the rear AC, but does it also have its own compressor?

I know the refrigerant lines run from front to rear, so I assume they run from a shared supply.

My understanding is that unless there is an obvious line/connector type leak that the most likely culprit will be a leak in the the compressor and that they are usually replaced, not repaired. Does that sound about right?

I am currently in tear down mode to get access to that area of the van. That involves removing some basic shelving units and some factory trim/walls which I have experience with.

But any tips or guidance with regards to the AC issue are welcome. Thanks.

[JWA]

I recently removed my rear factory A/C unit completely---that green fluid is the system oil. It would appear the rear A/C evaporator is leaking, the oil coming out the drain normally used to catch and expel condensation.

The factory A/C systems are essentially just one "loop"---front and rear share the same compressor, accumulator and condenser. Front has an orifice and is nearly identical in operation as a van without factory rear air. Rear uses a thermostatically controlled expansion valve to adjust cooling according to the heat load in that space.

At this point you'll need to replace the rear evaporator---once you've uncovered the rear A/C case the evaporator should be accessible by removing just the outside of the case. After the case is separated you'll need spring coupling disassembly tools in order to physically remove the evaporator coil---easily found and used if this will be largely a DIY project.

Do be sure to carefully inspect the hard refrigerant lines running front to rear---they're NOT easily accessed but using a UV lamp if any leaks are present they will be easily seen. These lines are notorious for leaking due age or mechanical wear from vibration or rubbing against something.

Glad to help further if I can---others here will have some input as well I'm sure. Do keep us advised of your progress please---best of luck!

[carringb]

Yup. With the dye coming from the condensate drain, it's somewhere in the rear evaporator loop. The stock evaperator is fairly well isolated form vibration, so IMO its unlikely to fail unless it was moved from the stock housing, or damaged during the build (stray screw?!?).

What is more likely is a bad o-ring at one of the quick connects back there. There are a couple for the evap itself and another for the orifice tube. Either of those components are easily swapped once you get all the panels off. The orifice tube is only a $10 part.

The hard lines running back to that point are a PITA as JWA mentioned, but also the least likely culprit. Usually those leak above the rear tire, from either salt corrosion or rock damage. Or in my case, at the firewall because my header melted a bracket allowing the lines to vibrate against the edge of the firewall.

[joefromsf]

Thanks Guys. Will get back to this tomorrow, as I have all day plans elsewhere today.

[arctictraveller]

Most folks know this but some may not, but any work on the lines or the evap will require the system to be evacuated, hopefully by recycling the refrigerant. If it's already empty due to the leak, it's best to pressurize it with dry nitrogen to locate the leak. Once repairs are made, the dryer may need replacing and then it will have to be pumped down (a vacuum applied to remove any moisture) prior to recharging. The point is, this is not a typical DIY repair, it requires special tools and training. Best of luck.

[Czar308]

Originally Posted by JWA

Do be sure to carefully inspect the hard refrigerant lines running front to rear---they're NOT easily accessed but using a UV lamp if any leaks are present they will be easily seen. These lines are notorious for leaking due age or mechanical wear from vibration or rubbing against something.

x2 on this.

Dealing with this right now. There is a "high pressure" 3/8" rigid line and 5/8" rigid "low pressure" return line under the body connected to the 2 rear rubber "jumpers" hoses who's ends disappear into the van and attach to the evaporator. In my case both lines showing corrosion under the plastic clips that secure them to the body and leaking from the 5/8" line. As soon as you find someone to ship it due to its length,the replacement 5/8" line cost me almost $300 . The smaller line on the other hand can be got for under $60 online. Similar price difference for the "jumpers" about $30 for the "high pressure" compared to the $70-$100 for the low pressure side. Just as an aside, any ideas why the price disparity?

[joefromsf]

OK, I got my rear driver's side shelves removed, as well as some of the interior trim and wall panels associated with passenger vans. Here is what I have now exposed. Note that there is no evidence of the AC leak on the exterior of what is visible.




I assume the circular assembly just left of center is the blower for both rear AC and heater. And below that in the rectangular section of plastic is the rear AC evaporator, correct? With AC refrigerant lines coming in on the left?



Left of the blower where it says A/C is the output duct for cold air. Here is a pic looking down into the duct from the top where there I see evidence (green dye) of a leak within the assembly. I also added a zoomed in photo.










So is the leak in the evaporator or something else located nearby in the black box assembly?

Based on what others have said I'm fine not tackling the actual repair myself, but can anyone assure me that I have provided enough access for the proper repair to be made or do I need to also take off additional trim and panels to the right (a lot more work since that is where I built my house battery and electrical component box).

Again thanks for any insight.

[arctictraveller]

Prior to knowing exactly where the leak is located, it's hard to say how you can get to it, but it must be accessible to work on it. You could try looking around and under with a mirror on a stick to see if you can see obvious signs of leakage, but it has to be coming from the evap assembly, the hose connections or the hoses them selves. If your system has had UV die injected, a black light may show up the location. Many professionals will pressurize the system with nitrogen, then use a soap solution sprayed around suspect areas to look for bubbles, but they have to be able to get access to possible leak areas. Can you pull the blower motor to get a better look inside?

Another thought: are there coolant lines run to the back for heat? That sure looks like coolant that's leaking out. By the way, if the original shop said it was repaired and it passed a pressure test, but was actually still leaking, I'd want to have another chat with them for a warranty claim.

[Czar308]

At work right now, but IIRC all you will see is air diverter and the inside of the ducting. I would pull the blower motor, but only to get it out of the way. It's just 5 or 6 screws ( 5/16" hex I think) a wiring connector and rubber duct.

If you are set on getting eyes on the evap core, start by remove 2 bolts ( yellow arrows) that secure the auxiliary hvac unit to the van.

Since you have the forward interior trim in place , I think you need to remove the forward heater core cover, 6 more screws, (same as the blower). The second photo shows the inside of that forward panel and how that cover and duct mates with the heater ducting. No fasteners just a little foam. With this cover removed i suspect you may now have enough wiggle room

Now this is where it gets tricky, since I assume you want to keep the fluids in plumbing and you have the forward panels in. You probably need to cut the ziptie for the hoses running forward to the heater core. You should be able to pull the entire assembly up 3-4", enough to get either a small 1/4" ratchet or better would be 1/4" bit ratchet handle and get the lower screws out(red arrows). 2 in the front easy, 2 in the back will require some finesse. The top of the housing should now be free. You should be able to lift it straight up and your evap core should be completely accessible.

I was able to do this without disconnecting any hoses, but I had all the interior trim off. Good luck.

[joefromsf]

Yes, I plan to return to the dealer to discuss prior work. At this point I am just trying to make it easier for them to access the unit. The only evidence of leaking seem to be inside the unit, which makes sense since it exits the unit thru the drain hole under the van which is part of the black molded plastic.


Thanks for the pics and tips for removing the plastic covers for the unit Czar308. I don't plan on touching any and lines, just trying make access easier to reduce labor costs.