2006 evaporator core

[banshee365]

Hey guy's. I think I've got an evap core leak on my 286k mile BRM Jetta along with a sticking RCV. The compressor was replaced at a dealer in 2013 or so by the previous owner. I don't have an AC machine so I have to take my stuff to a shop for that part of the work. I had them suck it down and recharge it as well as diag any leaks with a sniffer. They came back saying the only leaks were the two valves at the ports so they replaced those and charged it back up. They pulled like .5lb of refrigerant from the system and added the 1.16lb back to it. With the RCV sticking the air really didn't work any better and then I started noticing a refrigerant smell from the vents when you first turn on the blower. There really is any other way that I know of for that to happen other than a leak in the evap case.

I already have the RCV in hand from polar. I could pay to have the system sucked down, I replace the valve and then have it recharged and see how long it lasts but that seems like sort of a waste if I know the evap core is leaking somewhere. I've combed through the board a bit on evap cores in the MkV's and it seems they aren't very common to go bad. That makes me a little skeptical on going through this whole job but my nose isn't lying when it comes to the small when you first turn on the blower.

I wanted to get some opinions on what some others would do in this situation on whether to just replace the RCV and roll with it or go all out and replace the evap/expansion valve and RCV at the same time with one AC service fee rather than two at different times. I also have an RCD-330Plus coming in from China as well as needing to do the headliner. All of those can be done together because some of the labor and work required overlaps each other.

 

[oilhammer]

I have never seen nor heard of an evaporator core leak on an A5. I would want to be darn certain it was actually leaking before tearing into one.

I'd shove a sniffer into the dash vents and drain tube as well as maybe into the cabin filter cavity (after the filter is taken out) and try and verify.

 

[banshee365]

I have never seen nor heard of an evaporator core leak on an A5. I would want to be darn certain it was actually leaking before tearing into one.
I'd shove a sniffer into the dash vents and drain tube as well as maybe into the cabin filter cavity (after the filter is taken out) and try and verify.

Agreed, that would be ideal. I had an HVAC guy out repairing a unit at work the other day and ran a couple question about sniffers by him. He was telling me that you have to be pretty close to the leak to get a hit with a sniffer and if you get a hit from the vents it's really coming out of there fast. I do not have a sniffer and have already had a shop tell me I don't have any leaks after then turned the blower off for a minute or so then turned it back on with the sniffer in the vents. I don't think that was enough to detect a leak.

When I got in the car this morning after it sat overnight and turned the blower on I got a very very strong smell of refrigerant from all of the vents. I haven't gotten a positive from a refrigerant sniffer but my nose is telling a totally different story. With the evaporate/expansion valve being the only place that refrigerant enters the cabin I have to wonder, even with how uncommon an evap leak may be in these cars, where else could that smell be coming from. It's not sucking it through the blower case intake. The smell is instantaneous when the blower comes on after it's been sitting a little while.

If I do end up doing the evap core, and considering how uncommon the failures seem to be, I may go the route of a salvaged core from the u-pull-it. It's $30 vs $300+. I would replace the expansion valve with a new one and new o-rings for the connections.

The car can be sitting only 5-10 minutes to notice a very prominent smell of refrigerant from the vents when starting back up.

 

[oilhammer]

I have no idea what you are smelling, but if there was that much smell, the system would be empty in a day.

Maybe change the cabin filter and spray some Lysol or similar in the HVAC case and see if that changes anything.

R134a does not have a super strong smell.

 

[banshee365]

I had the system charged to 1.16lbs about a month ago. I've continued smelling a strong refrigerant/pag oil smell from the vents when the blower motor is first turned on. It almost made me light headed a few times. It's very noticeable.

I know for sure that the RCV is sticking. Whatever slight cooling effect the system has to the cabin is non-existent for the first 10 minutes. After a while it starts to cool slightly.

Today I had the system evacuated off the same machine that it was charged with last month. The plan was to just evacuate the system and change the RCV. But I know, based off of what my nose is telling me, that it was going to be partially charged from the leak. Sure enough only .54lb came out of the system. I know the scale is accurate because the last time I was there they evacuated and charged the system it was within .01lb.

Being that the general consensus is that the evaporator cores are robust on these cars, I will probably go for a salvaged core with a new OEM expansion valve. There really isn't anywhere else the refrigerant can be leaking. They ran a sniffer over every joint and potential leak source forward of the firewall. The system has UV dye in it and there isn't a spec of dye anywhere under the hood or around the condenser.

 

[banshee365]

Here ya go oilhammer. 2006 Package 1 Jetta TDI. The leak is clear under the UV light. The core also has PAG oil residue down one side of it. You say you’ve never seen or even heard of one leak. With that being said, I chose to go back in with a salvaged evap core. If they never leak I felt it may be a safe bet to use a salvaged part. But, with the amount of work this has taken to get to this point I’m a little skeptical.
Sorry if the images are a bit large. My internet is down and I’m having to do all this with my phone.

 

[banshee365]

The AC is working like new again, finally. That was a big project. After replacing the evaporator core, RCV and expansion valve, I removed the lock carrier to replace the radiator, dryer cartridge, and clean the condenser.

It was all worth it as it’s super hot in FL right now. No more refrigerant smells from the vents and the air cools in short order after engine start.