Complete Repair of BOTH Blend Doors on Porsche 911/Boxster (fix foam blowing out the vents w/plugs)

This video shows how to fix the “foam in vents” problem and repair both the HVAC blend doors using port plugs for a Porsche 911 (996 and 997) and Porsche Boxster/Cayman (986 and 987.)
Parts and Tools:
UPDATE: I just learned from the TDIclub.com forum that the person who was selling these plugs on Ebay passed away. The STL files are available on ThingVerse. You can use PrintAThing.com to 3-D print the STL file using ABS plastic.
printathing.co...
STL: thingiverse.co...
Former Source for plugs:
DSP Blend Door Foam Fix for VW Golf Jetta Beetle Passat: www.ebay.com/i...
Nashua 361-11 Foil Tape: amzn.to/3tnoxob
Permatex RTV: amzn.to/3rfe8bq
Milwaukee M12 Oscillating Tool: www.homedepot....

[@ProjectBiehlmeister]

UPDATE: I just learned from the TDIclub forum that the guy who was selling these plugs on eBay passed away. The STL files are available on ThingVerse. You can use PrintAThing.com to 3-D print the STL file using ABS plastic. (The STL file contains 4 plug sizes, but you only need 2 of the sizes as shown in the video.) printathing.com/order/ STL file: thingiverse.com/thing:5188776

[@cheffromage]

2001 996 C2 here. Wow. Many, many thanks for such a great fix. The plugs make this so much better than using duct tape. Got my plugs from DSP via eBay in about three days. A little fear and trepidation before I fired up the oscillating saw and cut into the duct, but that was perhaps the easiest step. (And I must say, the first person to cut into the duct in this way was either a fool or a genius. I can't imagine he/she knew with certainty that the doors would be accessible once the duct was open. But they are.) Cleaning the remaining foam and its degraded adhesive backing was a real pain, since it is ON BOTH SIDES OF THE DOORS. So you have to stick your fingers through the holes and sort of wipe off the backsides of the doors. It feels like a real victory when you pull out a piece one inch square. By the way, once the duct is cut, the opening is only about 3" x 4", so if you have big hands good for you but you won't want to try this fix. Once the foam is gone, the rest is quick. The plugs are fairly easy to place and once the sealant has set you can turn on the fan, actuate the doors, and watch the remaining bits and pieces of foam fly like snow out of all the vents.

[@ProjectBiehlmeister]

I’m glad the repair worked well for you!

[@aliciaesmay6820]

2001 996. I had the same trepidation cutting into the duct. I did buy an oscillating saw just for this and I’m glad I did. Once the plastic was cut… my immediate thought was “wow, I sure did watch a video on KZbin and took a saw to my car” … but I knew it was going to work. Demo on anything is that leap of commitment. 😊

[@SkywalkerPMs]

Yep, I need to do this my 996.

[@bloodystinktube321]

It definitely affects 987s as well. Both of mine have had it.

[@garryyeung6286]

I did it at front, and use magnetic stickers instead.

[@ProjectBiehlmeister]

Can you provide a link to the magnetic stickers you used? Were they strong enough that you thought they would never come off of the flaps?

[@davidluke3289]

Cost over $4K for the dealer to fix the foam problem in my 987.2. They said the evaporator box needed to be replaced.

[@ProjectBiehlmeister]

Unfortunately, full replacement of the assembly is the only solution Porsche lists in their system. The entire dash and center support assembly has to be removed, which is extremely labor-intensive. Hopefully the replacement unit has a different, foam-free design.

[@thefreedomguyuk]

Interesting. Only this morning I noticed some odd fluff on the floor in my old 996. Could be this.

[@ProjectBiehlmeister]

Yes, that foam is definitely from the blend door.

[@andrewmangum8391]

Why you silicone do these not snap into place the ones I have have a lip around them like Tupperware

[@ProjectBiehlmeister]

The ones I printed had a lip as well, but there wasn't enough engagement to prevent them from popping out the first time you hit a bump. The plugs aren't really flexible enough to fit perfectly and not pop out. RTV guarantees that you won't have to re-do the job later. Definitely use RTV on the plugs.

[@abdelhassand]

Can’t seem to find these on eBay anymore. Anyone have some boxster foam wafers for sale

[@ProjectBiehlmeister]

I just learned from the TDIclub.com forum that the person who was selling these plugs on Ebay passed away. The STL files are available on ThingVerse. You can pay a printing service to 3-D print the plugs using ABS plastic. www.stlfinder.com/model/mkiv-vw-blend-door-repair-plugs-41wCkIfS/4975799/

[@AnxiusOne]

Does this work on the 2007 porsche cayman? Also the holes now being plugged does not affect quality of AC or anything?

[@ProjectBiehlmeister]

This applies to a 2007 Cayman. It’s for all 986/996/987/997 cars (1997-2012). The holes are not supposed to be open. They are covered by foam from the factory. The foam needs to be fully removed before installing the plugs (or applying the aluminum tape instead of the plugs - both methods work.)

[@davidluke3289]

Should have designed them with grips on the back. But as it is, you made a mess. Tape should have been applied over the plugs, once dried and in place.

[@ProjectBiehlmeister]

Plugs and tape would be a belt-and-suspenders approach. Either solution should be fine by itself. As far as it looking messy…I hope to never lay eyes on those blend doors again.

[@locodriver2017]

Any reason not to use epoxy rather than RTV? I don't think the temps get high enough to be a concern. In any case, when I opened mine up, I found that only the large oval holes to be missing most of the foam; the smaller round holes on the other blend doors still had all of the foam intact! I'm not planning on touching them at this time; only plugging the ovals.

[@ProjectBiehlmeister]

I definitely would not use epoxy. Not because of durability concerns, but because of it making a mess and it being very difficult to remove if it falls in the wrong place. It could end up preventing the door from properly moving and would be difficult to remove. I recommend doing both doors and all holes at the same time. You’ll have little chunks of foam coming out of the vents for years otherwise. Just pull as much foam off the doors as possible and then install the plugs. It won’t take that much more time and then you never have to worry about it again.

[@mikematheny4552]

@@ProjectBiehlmeister. I looked on EBay and found both the DSP ones for about $31 and then two other brands each for about $9. They all say they go to the Passat. Are these the ones? Is there any info on the alternative plugs? Thanks, Mike

[@ProjectBiehlmeister]

I don’t have any experience with the other brands, but if they all fit the Passat, then they should work for the Porsches as well.

[@poco1174]

Once you have owned a Porsche you realize German engineering and craftsmanship is a myth. I have owned 6 and all had serious design, craftsmanship and engineering problems. The delaminating doors on my 981, to the incessant oil leaks on my ‘79 SC. 944 dashes and overheating, 996 IMS issues, this problem on my 987, bore scoring, replacing whole engines on GT3s, ……………any Porsche owner can add to this list. They can make one helluva race car and track car, and fun sports car. But, be prepared. The old adage that says these are expensive cars and you may have the money to buy, but you also need the money to repair them. I know this will cause some angst and anger, but these kinds of problems have plagued the entire model line since the 70s.

[@randominternetuser2888]

I would not suggest this method at all when you can go in through the heater core in the front and not have to hack your vent open and tape it shut. That method allows removing a blend door completely out and properly fix it instead of having to cut the oem unit into pieces. Don't do this to your porsche 986 or 996. The plugs are a good idea though, unless they fall out inside the ac module and block the door.

[@ProjectBiehlmeister]

I think what you don’t realize is that only 1 of the 2 blend doors is accessible via the heater core removal method. You’ll still have foam blowing out the vents and improper mixing of the air if you don’t address both blend doors. Also, the blend door method requires taking a hacksaw to the bushing cover and then repairing it. Both methods require cutting and repairing something that wasn’t meant to be cut. But both repairs are completely hidden and preserve all original functionality. The only “correct” way to do this repair is to remove the dash and HVAC unit. That’s about a 20 hour job, and much more chance of not reassembling something. I don’t recommend it.

[@gregwhaley4017]

@@ProjectBiehlmeister definitely agree that removing the dash is not the way to go. Since you are familiar with the tape method of covering the vents and now that you have completed your repair using the plugs & RTV, would you still go the route of using the plugs if you had to do this procedure on another car? Or would you use the tape? Thanks for the video and your feedback!

[@ProjectBiehlmeister]

To be honest, I think you are fine with either the tape method or the plugs. The only consideration is how durable the adhesive will be longterm. The aluminized tape seems to be very durable. But RTV is perhaps a better known and more trusted automotive adhesive, especially at higher temperatures. I would probably do the plugs if I did it again.

[@ronp1524]

Does this work on 996.2 ?

[@ProjectBiehlmeister]

Yes, this works on the 911 as well. 996.1, 996.2, 997.1, 997.2.