Lessons from foam out of air vents fix

Recently I needed to repair the flaps in the air condition on my 2000 C2 996. I decided to pull the dash and air conditioner to do the job. Thought I'd share some of my thoughts from this. This isn't a how-to. Just want to capture a couple of thoughts on this for next time. 1., I had a local shop evac and capture the refrigerant a couple of days prior to starting the job. I have my own AC vacuum pump and AC manifold so testing and recharging isn't an issue. 2. I've had the dash out many times (I've owned this car since Jan 2002) and I'll yank it when ever I need to do any wiring or testing under there. It's just easier. That said, this was the first time I'd removed the center support of the retaining frame and center air duct (what Porsche calls the Air Distributor) Very sorry I didn't take a photo but the only trick with the disassembly of these two pieces is getting to the screw on the top rear of the Air Distributor. The defroster vent doesn't pop out or out of your way. So you need to move it forcefully to the left and towards the windshield. I then found I could use a standard hex driver to get to the screw. There is a big 2" pin on the retaining frame that plugs into the center air distributor. It is two tight down at the tunnel so I put the two pieces together first and then put them into place. I then installed the screws on the air distributor and the retaining frame. This allowed me to wiggle everything around to get things properly lined up. 3. Take careful note of how your wiring routes to switches and connections. Especially in the center console area. Also, you will likely find the harness tape is falling off. Recommend you have a couple of rolls of wiring harness tape on hand. Be prepared to retape almost everything. 9mm is almost what the factory used. I get mine on ebay. See photo below. 4. I had, like others, planned on just using foil AC tape to restore the two flaps. But I found that this left sizable gaps around the flaps. See photo 3 below. I really want AC when I need it and heat when I want it. Fortunately, my local HVAC shop had what I think is just the right stuff. 5. Final thought, doing this job with the air conditioner out of the car really helped me get the job done to my satisfaction. Not dissing on other ways to do this. I have the time, so I elected to do it this way. I was doing other things while in there so it is hard to say how much time this took but I'd say it took two full days of plodding and no rushing. And if you are wondering, I am very happy with the results. Cold is cold and hot is hot. 9mm wiring harness tape. Don't use electrical tape. Electrical tape will leave a nasty residue. Foam tite. Worked like a champ over the foil tape. Testing the flap with just the foil tape. You can see the large gap at the upper right. There is also gaps all around it. The inner flap is the same way. Hard to see but the foam fills in all of the gaps. I did this on the inner one too. By having the unit out of the car I was able to really test and tweak things to make sure the flaps could easily move yet block the air that they needed to.

great work. thx for the notes. did you reach both flaps through that opening?

Thank you. Sorry, I didn't mention it but the whole unit pops in half. Both flaps completely accessible. About 16 little bolts. Most on top a couple or three you undo from the bottom of the unit. One is way down in a crevice but you can reach it with a 1/4 drive with long extension or long torx driver. There is actually a third flap over to one side. I think it is for recycling the air in the cabin. Mine was in good condition (it had a different type of foam covering on it.) btw, Another advantage of this approach is it makes it much easier to clean that damn foam out of all of the parts.

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This is great thanks! I'm just getting ready to do this fix but was planning to go through the dash as well. Curious is there a write up anywhere on Rennlist on how to take out the whole AC unit? Or perhaps you might be willing to do one??

Thank you. Pulling the AC unit is pretty easy. I don't think I even bothered to research it but I wish I had as I spent an hour or so just looking at it, thinking, ok what's holding you in? It turns out that once you disconnect the water hoses & remove the heater core and disconnect the AC lines, there are only 3 nuts on the cowl side. And on the inside, once you disconnect the two wiring harness plugs, there is just a weird bracket on the upper left side held in by a bolt to the car and a clip on the AC side.. And the thing litter-ally falls out. Unless you forget to disconnect the drain which I did and it is on the bottom left of the unit. I knew I should have taken a couple of photos. I'll try to do one of the cowl area in the morning. I think I have an interior photo that I can use. I'll try to add the info and photos up top (if I can) so everything is together. If not, I'll add it in here.

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i've made one many years ago when fixing a leaking evaporator on my 01 Boxster. in most parts it should be the same. i made it in 3 steps and you can download it from my google drive. https://drive.google.com/file/d/1jr2...usp=drive_link https://drive.google.com/file/d/11ZZ...usp=drive_link https://drive.google.com/file/d/12si...usp=drive_link

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I have this same issue on my mk1 Audi TT. The design looks the same. Do we know if the original foam filled the gaps around the flaps? And does anyone know why the holes (covered by foam) are there in the first place?

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Fantastic! Thanks for sharing.

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no foam around the flaps. The holes are there for weight reduction, hence the crappy thin foam the OEM part uses. My Boxster was sold to a friend, so I can confirm that 11 years later the AC system still works perfect with the procedure I did.

Here is another nice write up on the procedure. https://rennlist.com/forums/996-foru...total-fix.html

the holes threw me too. My thought was that they help reduce flexing & warping during heat and cooling because they are metal. The cynic in me thought they would help make sure the cheap foam they used would deteriorate quicker, making the flaps useless when that happened, thus insuring they sold more air boxes in the future.... As to the sealing around the edges of the flaps and that notch on what I call the front flap. I found that if the foam extended past the edge of the flap just a 1/8" or so, it provided a good seal. That seemed to be how it was originally (I didn't quite pay enough attention to the old foam) and seemed right. Also, as the interior flap is used to close off the heat from the heat exchanger. I really think that you want a good seal there. And there is no notch in that flap. And I'm in Key West. Regardless of design, 10 months of the year, I don't want any heat getting past that flap. However, the notch on the front flap is something else. I agree with Meirschwartz - In retrospect, I think there is a reason for the notch. Likely to always allow some minimal of air to pass even when closed. I'm not noticing any issues with air distribution (I'm not finding myself fiddling to get the air right) but I think if I were to do that flap again, I'd cut the notch out of the foam.

Many moons ago I read that the original foam was used to allow a small amount of air to flow through them. I've had my flaps covered also, and the system seems to work just fine. Only now I don't get pieces of foam blowing in my face.

The foam is for noise reduction. Mine was fixed with thin cardboard from a UPS envelope glued on with 3M 90 spray adhesive many years ago and is still working great.

I commend everyone that has done this job, especially the OP with removing the entire blower unit. That's a huge task IMHO. I guess I'm spoiled living in the south with it's mild winters. The blend door problem has never affected any of my Porsches heating abilities on average with the exception of one occurrence. One year, our 2002 996 coupe really struggled in AUTO mode when my wife and I took it on a winter trip to the mountains. It was bitter cold outside with freezing temperatures. Simple work-around was to deselect the cold AC (i.e. snowflake icon), select recirculate, and then turn the thermostat to "HI". After that, it was blowing hot air again. We turned the fan down to low and it was super hot inside the car.

Question what does this foam do? I have seen other posts like this but wondered what it does, since I have bits and peices come out of my vents, when I started to use the heater in the winter time in AZ. I've had zero issues in the winter time when I running the heat, in fact it was pretty hot. Last week it was around 82 in Scottsdale and ran the AC all day on my drive around town. The AC was very cold, but I have to wonder how it will be when it reaches above 100+ temps here? I dont plan on runnng it much in the summer just due to the extreme heat

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I think it serves two core purposes - to seal and to attenuate the acoustical noise from air movement. I don't think it was ever intended to be an air diffuser as some have thought. One thing we can all agree on... it doesn't last. jmo