john0719

I have a 2004 996 GT3 which lately when I turn on the air vent inside the cabin, very fine, small sponge-like debris would blow out the air vent. I've check the cabin air filter and everything seemed fine and there were no sign of such material debris in the filter or filter housing. Anyone one know what the source of this debris could be from? Thanks in advance for any thoughts.

Ahsai

The foams are part of the internal flaps and seals of the air distribution box. They deteriorate in time.

john0719

Should I be concerned by replacing the air distribution box or leave it as is as it really has no effect on the function or performance of air flow into the cabin?

Gator996

Over time it will affect the performance of the A/C and heat. The foam covered flap prevents the hot and cold air from mixing. The flap is inside the heater core. I just repaired mine a few weeks ago. It is not overly difficult to do. Porshce's answer is a new heater core which is not cheap. The picture is the flap out of my car. It should be completely covered in foam. You can see that it has entirely disentegrated.

frisbee91

I have the same issue. One of these days I'll clean out the air distribition system and replace some of the gasketing and foam.

DBJoe996

Welcome to 10-15 year old car ownership! Mine did that..cleaned it out with the shop vac while running the fan on high. Opened all vents and the floor vents. Had to do it a couple of times then it stopped. I figure with the high $ to replace I'll just live with it. I have not really noticed any difference in the HVAC modes, but I live in Florida so mostly just AC on all the time.

DB's997

Gator996,

Could you detail how you repaired yours? Mine is completely destroyed from 14 years of age.

fpb111

One fix is documented here:
http://www.renntech.org/forums/tutor...the-procedure/

Gator996

That is the diy I followed. Let me get a little free time at work today and I will describe the process.

eagle11401

Thanks for the link. Mine has been getting worse and worse this summer. This morning I had a good size chunk actually blocking the entire center vent on the passenger side. It's ridiculous how hard this stuff is to get out of the carpet if it gets smashed in to it.

FRUNKenstein

Having the same issue for the past year, just never got around to messing with it. Always assumed it was the cabin air filter somehow disintegrating, even though I just replaced it and the old one looked fine. Now I know what it is and how to fix it cheaply without even spending any time or effort researching. God I love this website.

Ahsai

You can get the VW adhesive foam pieces designed for this purpose

See http://forums.thecarlounge.com/showt...ater-Box-Flaps

Should be available here http://www.busdepot.com/155298121

Gator996

The tutorial posted above is pretty self explanatory once you start taking things apart. The pictures were not the best and I didnt document it very well with pics either.

The goal is to get to the flap that is inside the heater core. You need to remove the bottom windshield trim, the wiper arm assemblies and some bracing in the frunk. There is a black foam piece covering the heater core assembly. Careful, it is just glued on. There are two coolant hoses that need be removed first. The clamps are super tight. Once the hoses are off you can unscrew the top of the heater core box and then pull the core out. The core is the mini looking radiator thing.

There is a black cap that holds the top of the flap in place. The only way to remove the flap is to Dremel of the top of that cap. It is a bit scary at first but just nip away at it very shallow until you reveal the inner cap. The inner cap will pull up and out. It is more of a plug than a cap. You may need a screwdriver to help pry it out.

Now that the top is free, you have to contort yourself under the dash on the passenger side. Refer to the DIY. You need to undo a few screws and release the bits that are holding the flap in place from the bottom. It is really uncomfortable unless you are under 4'3 and less than 75 pounds.

Installation is the reverse. I used 1 inch wide two sided window seal foam to cover the door. I then wrapped it all in duct tape. I could have bought the part that Ashai has mentioned but I had this stuff on hand.

The picture I took shows the opening and what is what. I only took one picture during the whole process. You may need to blow it up to see the flap in place and that cap that must be gnawed off.

I would rate the job a 6 on the difficulty scale and that is pushing it. If anyone decides to tackle the fix, I can certainly help you through the process. Feel free to ask.

medent

I thought that the "always on hot" issue I had was due to the foam being lost from the flap. But I have since found out that it was because the hot/cold arm from the servo had fallen out where it contacts the lower tab of the flap.
Here are a couple of photos of the arm. One with the piece attached, the other separated. I have also attached a couple of photos showing where the open end attaches to the servo (pink) and the hole where the other end inserts.
I need to know how the separate piece stays in place. Are there supposed to be tabs to hold it in? Or do I just have to push it in firmly?
If I need to get a new piece with tabs, any idea where to buy it? I'm sure that Porsche will ask me to buy the entire heater unit.

OKB

theres also a solid vinyl sponge 'foam' material that wont come apart available at A/C repair shops