E9 A/C Condensate Drain

ScottAndrews said:
Not sure how flexible the elastomer actually is. But I agree if it is pretty squishy, then making the top ring taller would assure a solid seal.

I am not super clear on the "indented slot" suggestion.

My original design had two grooves, one for the trans tunnel, and one for the mounting plate, but we thought it might be too difficult to seat both grooves. So are you suggesting making the barb smaller so it is easier to insert, but adding a stop above, so it doesn;t get pushed too far in? That seems like an interesting idea. Here's a version like that.View attachment 222120

View attachment 222121
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This is exactly what I was thinking. I used this part below and it clicked in perfectly to the tunnel hole. The top part was a bit too tall, and does not seat into the top of the bracket like the original or your design making it very hard to put on, but the bottom was spot on:
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Based on the measurements I made at Dons, I think the structure below is the right design. This may not work for vehicles that have a different morning plate or evaporator, since the idea here is to have the funnel extend about 5-7 mm below the tunnel. If the routing plate is taller, or shorter than 21 mm then the funnel will extend into the tunnel less or more. A few mm won't hurt anything but if it is a lot shorter, the funnel tip may hit the transmission.

The curve of the inside of the funnel is also important , since you want the evaporator tube to seal against the funnel. I have shown this in the cross-section diagram below (note this is a HALF cross section, since to make the part in 3D I revolve the section 360 degrees). The rectangle in the upper right represents the evaporator tube, which is 15 mm dia and 6.5 mm long. You can see it interferes with the funnel at the bottom by about 1mm, which is good. The funnel will deform slightly and seal the tube.

Screenshot 2026-07-10 at 8.32.46 AM.png


And here is the finished part.

Screenshot 2026-07-10 at 8.48.17 AM.png
 
i like it Scott. i think this will be great. i should have my gen 4 pieces next week and will try to fit them. if it doesn't work well, i will go to this gen 5 piece.
 
So the plot thickens...I was at my shop today and decided to measure the depth of the mounting plate on my car (1972 CS). It measures 11.5 mm from to to the bottom of the feet.

The one I measured at Don's was 21.5, and then measured by @rsporsche is 13 mm.

So it seems we have a fairly large variation in these plates...
 
i measured the distance from the top of the tranny tunnel down to the tranny today. it was 22 mm on my car.
 
rsporsche said:
i measured the distance from the top of the tranny tunnel down to the tranny today. it was 22 mm on my car.
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So that means there is some wiggle room on the length of the funnel, but still odd that there is so much variation in the height of the top of the mounting plate...
 
okay, i got my condensate drains from xometry. there is no way this thing is going to fit. the material is very stiff. the slot that fits into the mounting bracket needs to be deeper. i want to try it again without the bottom lock as there is no way that is going to compress to fit into the hole. Scott, if you can increase the thickness of the slot to 3mm (from 2), and use the no lock bottom, i think we will have a winner.
 
rsporsche said:
okay, i got my condensate drains from xometry. there is no way this thing is going to fit. the material is very stiff. the slot that fits into the mounting bracket needs to be deeper. i want to try it again without the bottom lock as there is no way that is going to compress to fit into the hole. Scott, if you can increase the thickness of the slot to 3mm (from 2), and use the no lock bottom, i think we will have a winner.
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What material did you have them printed in?

I'll update the file this weekend
 
 
rsporsche said:
okay, i got my condensate drains from xometry. there is no way this thing is going to fit. the material is very stiff. the slot that fits into the mounting bracket needs to be deeper. i want to try it again without the bottom lock as there is no way that is going to compress to fit into the hole. Scott, if you can increase the thickness of the slot to 3mm (from 2), and use the no lock bottom, i think we will have a winner.
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Yeah, I got some parts back made in TPU88, and they are not as hard as regular ABS or PLA, but not really "pliable"...

Need to find someone that can fab in TPU 85
 
ScottAndrews said:
I saw your post onthe heater and saw you had a red drain grommet. Did you print that with TPU 85? How soft is it?
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First of all, printing with TPU 85 is problematic because the filament on the spool is so soft that it causes issues with feeding into the print head, and the printing process itself can also be difficult.
In my opinion, TPU 95 is flexible enough to replace the original drainage funnel.
The fact that the material is harder and more rigid than the original makes it seem much more durable and resistant to the conditions at the installation site.
It is flexible enough to be installed in the opening at the base of the evaporator.
 
OK, I redid the part with a slightly deeper cutout. This should now be flush or slightly below the mounting plate surface. The cutout is also slightly wider than before, since the diameter of the evaporator tube is about 15 mm. So hopefully the tube will just slide inland drop down

The bottom tube is 12 mm OD. As noted above the hole in the tunnel is generally larger than this, and there should be a foam gasket/donut sandwiched between the tunnel and the mounting plate to see the tunnel hole from the car cockpit. The piece will extend between 5 and 15 mm down through the tunnel, depending on the height of your evaporator mounting plate.

I did some research and found a couple of fairly flexible materials. Based on their temperature ratings, it looks like TPU 92 A, which can be printed by Stratasys should work. It is flexible and can work up to 90 degrees C.

I'll let you all know the cost per part.

Screenshot 2026-07-18 at 8.13.52 AM.png
 
i can tell you that the hole in the tunnel on my 2800cs is 10mm. i am going to enlarge it a bit ... to 12 / 13 mm.
 
rsporsche said:
i can tell you that the hole in the tunnel on my 2800cs is 10mm. i am going to enlarge it a bit ... to 12 / 13 mm.
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Yeah, I think that was a retro fit car, right? I think the holes range all over the map. But there should be a foam donut-like gasket between the tunnel and the mounting plate as well. That seals off the tunnel from the car, so the funnel is not doing all the work.

If you do about 12mm then the end of the funnel should seal fairly well, even without the donut. Maybe runa bead of silicone around the edge of the hole in the tunnel before putting the funnel in place...
 
Been having an email discussion with a representative from Stratasys about materials. He has a material TEPU 50A that is thermally stable, chemically resistant and should be MUCH softer. I am waiting for the price per part. In small quantities these are looking to be about $50 each, which is steep, but for an unobtainium part, not that steep...
 

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rsporsche said:
foam donut was long gone on my car. i will put a bead of sealant around the opening when installing.
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You will want the funnel to pass through the hole into the trans tunnel, then seal around it, or put some sealant on the lower end, and then push it through the hole and engage the grommet end in the mounting plate. With a small tunnel hole, you should be good to go without the donut, and there should be no risk of the AC evaporator draining onto the floor of the car!
 
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