E9 A/C Condensate Drain

since i was going to enlarge the hole anyway. i think i am going to enlarge it a little more and put the e24 drain in it ... since a good friend here on the forum sent me one. going to pull the dremel tool out tomorrow and start working on it.
 
since i was going to enlarge the hole anyway. i think i am going to enlarge it a little more and put the e24 drain in it ... since a good friend here on the forum sent me one. going to pull the dremel tool out tomorrow and start working on it.
Yeah when those concours judges start removing the evaporator to confirm you have the correct drain you are going to be sorry!
:rolleyes:. Seriously, sounds like a reasonable plan
 
If I may jump into your discussion, gentlemen—I have a question.

Below are comparison photos of the original drainage funnel and a copy.

Is that slight misalignment of the tip a factory feature, or did it result from deformation?

I ask because I own the original, yet I never actually noticed that detail.

By the way, when selecting a filament to print this funnel, be sure to check the manufacturer's specifications for temperature resistance.
After all, the gearbox and driveshaft are located right underneath.
It seems to me that on a very sunny day—especially on a winding road—temperatures near the drainage opening could get quite high.
 

Attachments

  • IMG_1739.jpeg
    IMG_1739.jpeg
    217.4 KB · Views: 28
  • IMG_1738.jpeg
    IMG_1738.jpeg
    230.6 KB · Views: 29
  • IMG_1740.jpeg
    IMG_1740.jpeg
    191.3 KB · Views: 27
If I may jump into your discussion, gentlemen—I have a question.

Below are comparison photos of the original drainage funnel and a copy.

Is that slight misalignment of the tip a factory feature, or did it result from deformation?

I ask because I own the original, yet I never actually noticed that detail.

By the way, when selecting a filament to print this funnel, be sure to check the manufacturer's specifications for temperature resistance.
After all, the gearbox and driveshaft are located right underneath.
It seems to me that on a very sunny day—especially on a winding road—temperatures near the drainage opening could get quite high.
I'm not sure why that end would be offset. The original drains I have seen are symmetrical.
 
So, @rsporsche - I'm probably late to the party with this information, but truth be told I wasn't in any hurry to pull apart the dash of my 1979 M635csi parts car, primarily because I still haven't finished the transmission swap on my e28. However, I'm waiting on a part from Rock Auto, and I told Doug Dolan at the PVGP that I had the A/C motor for his coupe that he was looking for. Today, I proceeded to pull apart the dash and obtain for Doug a replacement motor. In the process, I took some pictures of how that little drain you are evaluating is implemented in the early e24s. Here is the bottom of the box that holds the evaporator and the motor:

20260728_172358.jpg


And here are a couple of pictures of the mounting plate with that little drain installed in it:

20260728_172425.jpg
20260728_172430.jpg


I can easily pull this mounting plate out and send it to you if it would help with your efforts to design an e9 drain.
 
So, @rsporsche - I'm probably late to the party with this information, but truth be told I wasn't in any hurry to pull apart the dash of my 1979 M635csi parts car, primarily because I still haven't finished the transmission swap on my e28. However, I'm waiting on a part from Rock Auto, and I told Doug Dolan at the PVGP that I had the A/C motor for his coupe that he was looking for. Today, I proceeded to pull apart the dash and obtain for Doug a replacement motor. In the process, I took some pictures of how that little drain you are evaluating is implemented in the early e24s. Here is the bottom of the box that holds the evaporator and the motor:

View attachment 223272

And here are a couple of pictures of the mounting plate with that little drain installed in it:

View attachment 223273View attachment 223274

I can easily pull this mounting plate out and send it to you if it would help with your efforts to design an e9 drain.
Can you pull off that mounting plate and show us the under side? I believe there should be a foam "donut" that sits under it. The hole in the donut being fairly large, and the hole in the tunnel being larger than the end of the drain funnel.

From what we have seen so far there are various different heights to that mounting plate, and different cars have different sized holes in the tunnel.

I believe the idea is that the foam donut seals the interior of the car from the trans tunnel, and the drain seals the top of that area while also draining condensate down onto the transmission (weird approach, I know).

S
 
So, @rsporsche - I'm probably late to the party with this information, but truth be told I wasn't in any hurry to pull apart the dash of my 1979 M635csi parts car, primarily because I still haven't finished the transmission swap on my e28. However, I'm waiting on a part from Rock Auto, and I told Doug Dolan at the PVGP that I had the A/C motor for his coupe that he was looking for. Today, I proceeded to pull apart the dash and obtain for Doug a replacement motor. In the process, I took some pictures of how that little drain you are evaluating is implemented in the early e24s. Here is the bottom of the box that holds the evaporator and the motor:

View attachment 223272

And here are a couple of pictures of the mounting plate with that little drain installed in it:

View attachment 223273View attachment 223274

I can easily pull this mounting plate out and send it to you if it would help with your efforts to design an e9 drain.
hi Chris, thanks, i already have one that @HB Chris sent me. perhaps somebody else might be in need ... or you might want to keep it for yourself in case you are ever in need.
 
@ScottAndrews - here are a couple of pictures of the mounting plate unbolted and flipped up. It appears that the ring you mentioned used to be there, but has turned to that fuzzy dust you see on the drain funnel and on the floor near the opening in the tunnel. This dust looks just like the dust the underhood insulation in my coupe created as it failed.

20260729_140510.jpg
20260729_140507.jpg
20260729_140458.jpg
 
I don't have AC in my car but it seems like this is sort of a kooky system that might be amenable to a better solution. Rather than a foam ring that is once again going to disintegrate due to time, heat and vibration, couldn't this be a rubber pad that sits there? If it has a hole cut through the middle of it then the drain plug could wedge down into it. I understand as well that some of you have different lengths, but it seems that the primary problem is if it's too short, not if it's too long. "Too long" just means it sticks out at the bottom, correct? Would making a funnel out of TPA with then a length of the longest one pictured above passing through a few mm thick piece of rubber to secure it into that rectangular cutout in the carpet be a reproducible system? Sorry if I'm stating the obvious or misunderstanding the setup.
 
i don't see the need for the donut / foam ring. i agree with JC, its going to disintegrate over time. if the drain goes through the hole you should be taking care of most of the issue - if not all of it. i think the original one was there and the drain dropped into the ring but didn't go thru the floor - the donut was supposed to deal with guiding the water to the hole. and we all know the end of that story - it disappeared
 
As to depth, here's a picture showing the underside of the bracket. Again, this is from an e12 based e24, so the closest thing to the next iteration of our cars as you are going to find.

The ruler is flat on the bottom surface of the plate, so with the 18mm depth of the brackets and the thickness of the plate, I'd say the surface of the plate is 21mm above the floor. The funnel is roughly 28mm long below the mounting plate.

20260729_153339.jpg
 
A couple of thoughts. I was out at the body shop today and told the guy about this part, and the fact that the printed ones were too hard. He suggested printing one and then making a plastic mold from the printed part, and then casting one in some flexible rubber compound. Sounds like an idea..

It seems we have various approaches to the interface between the drain and the floor and the mounting plate.I checked my car at the body shop, and like @rsporsche the trans tunnel hole is about 10 mm. The hole in the one Don had on a lift is about 25 mm or more.

I recall someone (@HB Chris?) saying that the AC option was delivered in a box in the trunk of the car, and installed by the dealer. I suspect that the original idea was Mohave a hole large enough for the drain to fit through, and the foam donut was there to seal off the cabin from the trans tunnel. However because of the variability of the installs, Suspect many cars had the drain (which based on @Ohmess's photos is clearly longer than the gap between he plate and the tunnel) smushed up against the tunnel, and a Chris says, the donut sort of guided the water into the hole (or didn't, in most cases....).

I think a better solution would be to make a 2 piece drain. One piece fits into the tunnel like a grommet, and has a hole large enough to accommodate the bottom of the drain, and then the drain is like it is. This way there is a seal onthe tunnel, and the drain is routed properly into the tunnel.
 
It was delivered as a kit but that doesn’t mean BMW didn’t predrill the openings. This is the case for the core support and firewall, both done at the factory.
 
Scott, the e24 one is 17mm wide at the bottom and 12mm wide of a drain opening. the top is 22mm diameter opening - 10mm down it is 13.5mm wide and at 15mm down it is 12 mm diameter. the overall piece is 33mm tall and below a mounting plate, it is 28.25mm. the pdf i posted originally was a drawing of the original e24 piece.

i am going to widen my 10mm hole to 18mm and slide the e24 drain in it ... and then put a bead of sealant around that. or i could make the hole bigger and put a grommet in it ... but i think the 18 mm hole is a better idea.
 

Attachments

Scott, the e24 one is 17mm wide at the bottom and 12mm wide of a drain opening. the top is 22mm diameter opening - 10mm down it is 13.5mm wide and at 15mm down it is 12 mm diameter. the overall piece is 33mm tall and below a mounting plate, it is 28.25mm.

i am going to widen my 10mm hole to 18mm and slide the e24 drain in it ... and then put a bead of sealant around that. or i could make the hole bigger and put a grommet in it ... but i think the 18 mm hole is a better idea.
Actually maybe do both! The grommet in the tunnel will make a better seal for the tunnel, and then goop the joint between the grommet and the drain.

Sounds like a nice simple solution.

Is the E24 drain available?
 
Back
Top