A/C drain

[A4.Rob]

I have done so much searching but I cant find the answer or DIY specific to the B6/B7.



Where is the a/c drain located?

I believe mine is clogged and I need to clear it out. When I turn on the system water soaks the foam behind the glovebox.

[jursch2211]

I don't think there is a drain for the A/C system. Working in the body shop industry in order to remove or replace A/C components we do what is called evacuate/recharge, and recovery. Anytime that you open up the A/C system you should replace the drier as that is what removes moisture from the air. Not sure if this is what you are looking for but hope it helps get you on the right track.

[A4.Rob]

I don't think there is a drain for the A/C system. Working in the body shop industry in order to remove or replace A/C components we do what is called evacuate/recharge, and recovery. Anytime that you open up the A/C system you should replace the drier as that is what removes moisture from the air. Not sure if this is what you are looking for but hope it helps get you on the right track.

There is an evap drain. When you use your a/c system especially on a hot humid day in the summer. Water comes out and sometimes a tone of it right beneath the car.

There are many DIY for other models.. B5 A4 and the A6, A8.

Can't for the life of me find any DIY's on it or the location. However lots of people discussing it in b6 forums as a possible reason for wet passenger side carpets.

[Seerlah]

There is no such thing as an AC drain. It is a toxic chemical. There are EPA regulations on how refrigerant needs to be handled. What you do is get a recovery tank, evacuation machine, and evacuate the system from either the low pressure or high side pressure port. After that, the filter/drier is supposed to be replaced every time the system is open to air. After the filter/drier is replaced, then you need to vacuum the system to boil off any moisture and take out air (min of 500 microns). After that, you can use the same refrigerant you took out and place it back in. But you would need to make sure that no air is in the system. That basically entails the purging of the lines when handling the refrigerant and the recovery tank should be new (best way to go about it). If you want to dispose of the refrigerant, you need to take it to the proper recycling facility. It can not be dumped into the atmosphere. It is a hazardous material.

There is an evap drain. When you use your a/c system especially on a hot humid day in the summer. Water comes out and sometimes a tone of it right beneath the car.

There are many DIY for other models.. B5 A4 and the A6, A8.

Can't for the life of me find any DIY's on it or the location. However lots of people discussing it in b6 forums as a possible reason for wet passenger side carpets.

Water condensate from the evaporator has nothing to do with the actual refrigerant in the closed system. There are 2 access ports for the refrigerant and those are the low and high side ports. The water condensate has to do with the property of removing latent heat from a median. In this case, that median is the cabin of your vehicle. Air has moisture in it. The refrigerant takes the latent heat, but the water content is still here. I'm not sure how the condensate system works on our vehicles, but it needs to go somewhere. That is the water you see dripping under your car when the AC system is running in the summer.

But OP, the drain above is what you must be referring to. Can't help you there. But hope that gives you a better understanding of your AC system.

[chad99]

I think the OP knows the above...all he is asking for is how to clear the drain

[A4.Rob]

Well the A/C drain is definitely the wrong term to use. I'm not talking about the refrigerant in the system.

Again the evap drain is what im talking about.. the condensation that goes through the drain and out beneath the car.

Here are examples on how to fix it on other models

A8 http://www.audipages.com/Tech_Articl...tordrains.html
C5 A6 http://www.audizine.com/forum/showth...-side-footwell

[Bobby417919]

I'm having the same thing.. I'm not getting any condensation water draining. Did you manage to unclog yours?

[A4.Rob]

I'm having the same thing.. I'm not getting any condensation water draining. Did you manage to unclog yours?

Turned out it wasn't the problem and wasn't clogged at all. On a side note I finally solved the water coming in on my passenger side carpet!

If you're looking for the tube that drains out the water, it is located on the left side of the passenger carpet. It is underneath the sloped section of carpet that goes up to the center console.

I can take a photo if you need any further direction.

[old guy]

[Bobby417919]

Where is that at. Front driver side?

[customa4]

Turned out it wasn't the problem and wasn't clogged at all. On a side note I finally solved the water coming in on my passenger side carpet!

If you're looking for the tube that drains out the water, it is located on the left side of the passenger carpet. It is underneath the sloped section of carpet that goes up to the center console.

I can take a photo if you need any further direction.

Where is that at. Front driver side?

It's the passenger side

[JayTheSnork]

after doing some digging, the pix above are not for a B6 A4, or more specifically, not for my 2005 B6 A4 Avant 6MT quatro.

pulling the glovebox allows you to see a hose that comes off the bottom of the lowest point in the center of the dash. the hose starts off round (flex connector, like an accordion) that turns 90 degrees and connects to the bottom of the duct. as it goes past the flex connector, it flattens out and gets wide, and runs down under the passenger side carpeting. I'm not sure if it can be disconnected at the base of the ductwork. my intention is first see if I can disconnect it and blow air thru it; if not, I'll put the car on ramps and see if I can find where it exits the bottom of the car, and reverse blow out the hose with little to moderate air pressure. right now, I have the car idling in the driveway to see if I get anything thru the hose on the gravel - as it might help me spot the drain (assuming it drains just a little...).

edit:

remove the glovebox via this post: http://www.a4mods.com/index.php?page...boxrattle.html but be aware, there are more bolts required to remove it than the OP stated (~10, vice the 5 stated). next, you'll have to pull back the carpeting as far as you can to get access to the AC drain line; it is as I stated where it is above.

the drain line does pull off the accordion fitting. ran compressed air at 25 to 30 psi thru it, and I could hear it when the blockage broke free. I dried the area under the fitting, and then let the car idle with the AC set as low as it goes for 15 minutes; after I went back to it, it was bone dry. success!

[old guy]

Stick some cardboard under the car to make it easier to spot. And would you mind posting up a pic or two of your drain configuration if you still have it open?

Cheers!

[Sodium]

For the record: Condensate Drain is in fact a refrigeration technical term. Having the drain get plugged is a normal problem on all AC systems. The evaporator on refrigeration systems gets cold enough to condense water from the air and that water needs to drain away through this drain. If the drain plugs, usually from mold or on cars sometimes leaves and debris, the condensate will overflow and make a mess. Nothing ruins things faster than fire but water is a close second.

That said, I just pulled my CCM from the driverside foot well and found a bunch of clear water that can't be attributed to rain so I'm guessing it's condensate and I've got a plugged condensate drain. But the weird part is that on my car this is in the driver's footwell and from all the descriptions above I'm having a hard time figuring out where the heck the darn thing comes out the bottom of the car.

When fixing residential systems we will usually attach a shop-vac to the 1/2" drain line at the exterior of the house. That seems to work fine unplugging the line and would seem to be a solution here too if I can locate the drain.

[13_C7_SC]

Where is that at. Front driver side?

He said on the left side of the "passenger" carpet...
The answer to your question is in the riddle lol

Sent from my Nexus 6 using Tapatalk

[19jdog]

I read this thread thinking damn that sucks. Well its hot where live so I use the ac on the way home from work. This morning when I drove to work I smelled mildew. I'm sure my ac drain is clogged!

[LanceSupersad]

I believe I have this exact same problem; car smells like a "gym bag" or "mildew" or "musty". Bought my car from a friend, and he said, when he got it, the cabin air filter was ransacked by a mouse. He replaced the air filter, but said the mildew smell persisted. In my case, I am guessing the disaster that the mouse made had gotten into my drains. Coincidentally, my actual cabin air filter smells musty as well, but if I just remove it, the problem isn't resolved. As well, a charcoal filter won't do anything, since the smell is on the other side of the filter (at least in my car).

Reading online, there are a bunch of people with the B6 (I believe) and say that examples of THEIR drains being plugged is a musty smell, and your AC doesn't work until you start moving (I have both of these problems). I have no idea why driving will allow the AC to magically work, but it's a common diagnostic for whatever reason.

I've NEVER owned a car whose AC systems would get musty if you don't turn off your AC a minute before stopping ... and I've owned a LOT of cars. Also, humidity where I live is almost always near 100% in the summer, so when the AC is on, water is dripping quickly from the bottom of the car ... no such dripping happens from my car (but it could be dripping onto my cat and boiling away; I have no idea).

I'm going to have at cleaning that drain and report back. I'll take pics too, but my phone is garbage.

Edit: So, 100% sure my musty smell is inside the evaporator housing; turns out my phone was being nice and taking decent (for it) pictures. Also turns out the drain is easy to access, and there is even an upper access port. All of the underlines stuff are links to the pictures.

If you're looking to see if you have a blockage, I suggest removing the glove box for the first time; it's pretty simple now that I've seen it once, but it was nice this first time (with glovebox/without glovebox); it's only like 8 easily accessible bolts, and makes everything easy afterwards. I was coincidentally also fixing my glove box, so found this out by accident. This picture is of the passenger's floor area. "1" is the drain port, "2" is the access port (you can see where this is from the "without glovebox" pic). You can look into the access hole, but you'll probably need one of those snake cameras to see anything good inside (I almost "rented" one from the hardware store, just for kicks). I tried to take a pic, but the only thing I was able to see was a slight brownish-yellowish coating @ the very bottom of the evaporator ("3"), which somewhat looked like the stuff in the drain ("4").

I pulled back the carpet to expose the body of the tube, and the drain tube pulls out of the little rubber boot really easily. From there, you can easily move the drain around (it's a flat tube, so it bends a lot). I actually just blew into it with my mouth, but a compressor (which I don't own) would have been better. You could also easily vacuum out the evaporator end, or even run whatever chemical you wanted in through the access port and vacuum it out through the drain (which is my next plan).

I scaled all of the pics and named them "-small"; if you click a pic and want to see a bigger version, then remove the "-small" from the URL.

[LanceSupersad]

Thought about it again, and if there is debris that came from the filter, it would be stuck on the side of the evaporator that you cannot see through the access port. Also, in order for the AC to properly work, that side of the evaporator needs to be sealed from the interior side to ensure all air goes through the evaporator. Going to "rent" that camera from the hardware store and see if I can get to the condenser from the HVAC fan hole; no idea how I might get a vacuum back there if it's all packed with shredded filter bits.

[Luxus Panzer]

I think "1" is just a plug to and is normally used for cars with the AC in the glove box.

My car has glove box AC and I ran the piping from your "1"

[LanceSupersad]

I think "1" is just a plug to and is normally used for cars with the AC in the glove box.

My car has glove box AC and I ran the piping from your "1"

Ah, that makes sense why that thing is there (I presume you meant "2", as "1" is definitely the drain port for water). Regardless, it's a convenient port to look down into one side of the evaporator (unfortunately, not the side I want to see).

Edit: Glove box AC is hilarious; I guess if I wanted to store drinks in there?

[lyates1987]

Glad I read this thread. I get that musty smell every once in a while. The car's old so I might as well give it a check and blow out any debris that's in there. Glad my AC still blows cold. Texas is starting to turn into a grill

[LanceSupersad]

Ok, now bear with the crappiness of this pic; it's a picture of a really crappy LCD screen, using my equally crappy phone. I was really hoping the snake camera had a "save" option, but it doesn't. I might re-do this at night so I don't have all this glare, and maybe it'll be a little cooler than 90°F.
Pic of LCD screen

This is a crude CAD cutaway of what my posts are referring to (colours match).

So, "1" and "2" are labelled as you can see; that's the drain and (what I now know as) the glovebox AC port.

In my crappy LCD image, the red circled stuff (or red line, in CAD) is the "outside air" side of the evaporator. Unfortunately I wasn't able to capture it with my phone camera, but it is covered in tiny patches of what appears to be black mold. This is based on what I see with a pretty crappy camera, and it's daytime, so the contrast is extra garbage.

The magenta stuff is what would be the driver's edge of the evaporator, and is lined with what appears to be random balls of fluff (it's like this along the bottom as well); they've seemingly been pressed against the wall, and are going to be an enormous PITA to get out. Especially since they're probably soaked with water. In my case, those are almost positively either a mouse's nest, or the remnants of the mouse massacring the cabin air filter. They're also presumably the main source of my "musty" smell, and when they get soaked with water, are making the airbox nice and humid, helping to encourage whatever to grow on the AC core, and to help the mold to grow on the cabin air filter.

The cyan is the back of the evaporator box; labelled simply for reference.

My original plan was to just block the intake (where the cabin air filter is), and attach my shop vac to the HVAC fan hole, but unless I can somehow block most of the evap core and force those little buggers from the bottom/side, I doubt it'd work. Next option is finding a vacuum hose that is like 1/2-1" diameter and pushing it in there in hopes I pick up the shrapnel @ the bottom (the path from the HVAC fan to the evaporator is probably 1" deep ... as a guess). If that doesn't work, I will probably drill a hole in the side of the box (@ the magenta circle) and then cover it after I clean it out; effectively, this would work out to be the same as the glovebox AC port, but at a crappier angle. Another option is to try and "wash" them out; I hope I don't have to try and do that.

[LanceSupersad]

Confirmed, I have a mouse nest in my HVAC box; pricks. The "sample" was slightly wet (I haven't driven my car in about 4 hours), has mouse poo in it, and had mold.

Managed to clean out the evaporator with water; attached a hose to a small tube, and just blasted the chamber. Water spilled out of the bottom of the car (water want through the evaporator and out the drain), as well as came back towards the hole where I was spraying water into (the squirrelcage fan). Everything is waterproof in there, so there were only two ways out.

After I was done, I blew out the evap drain again for good measure. No more smell, and it looks like brand new (almost) in there. I sprayed some anti-fungal stuff in as well to try and get rid of the black mold, but I expect it would eventually just go away on it's own anyways.

[amiller]

Turned out it wasn't the problem and wasn't clogged at all. On a side note I finally solved the water coming in on my passenger side carpet!

If you're looking for the tube that drains out the water, it is located on the left side of the passenger carpet. It is underneath the sloped section of carpet that goes up to the center console.

I can take a photo if you need any further direction.

This was a week after replacing the wiper transmission. Wife was driving in heavy rain, and front seat passenger had water on her feet. I had flushed out a lot of leaves, thought I had left some plugging the drain holes under battery; later confirmed that those were not blocked. Then I found the threads about a/c evaporator drain hoses being plugged. Checked mine and they were not plugged.
I'd like to know what your solution was.