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Hood/DME compartment drainage???

10K views 13 replies 6 participants last post by  SeattleGraugrun03 
#1 ·
Long story short, there was water in the car. It wasn't the vapor barriers, or the sunroof drains, etc. I finally traced it to the compartment that houses the ABS unit, the brake booster, and the DME in the engine compartment. There was standing water here that collects from the windshield cowl. Think whatever drains that compartment was clogged, and eventually the water made it through the firewall and down the floor on the driver's side.

I don't believe the compartment has as many holes/drains as the drug bin on the other side, but I haven't been able to confirm. I peeled back the wheel well liner and found a small "drain" that I unclogged and the water drained. This seems like a terrible design, especially draining that much water (this is Seattle) through a compartment that houses all sorts of electronic and important bits.

Anyone know how this compartment is supposed to drain? I'm trying to get at it from the bottom rather than having to take out the booster and/or master cylinder. I don't think there are holes as big as the ones in the drug bin, or else it wouldn't get clogged as easily...

:eek:

Attached a pic of the compartment I'm talking about.
 

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#4 ·
You just said your DME compartment filled with water and that water entered the interior due to a drainage block. How is it not damaged? Facepalm yourself, nub. you need to explain yourself more clearly. I still don't know what you are trying to say/ask.
 
#6 ·
Hmmm... I get some water in my driver side floor board at wierd times. Only during very heavy rains, and even then it doesn't happen every single time. I've checked out every other thing. Maybe it could be something like this.

If the normal drain is clogged, it might be forced to drain into the car. I'll have to try and check this out.

Plus, I've got a hex socket stuck in that bin somewhere. I've love to have that back. Classic win-win.
 
#10 ·
E46Mango: I said the compartment that _houses_ the DME, abs, and brake booster fills with water... "I finally traced it to the compartment that houses the ABS unit, the brake booster, and the DME in the engine compartment. "


If you look at the pic it's just like the empty bin on the passenger's side, but it has the DME and wiring harnesses, the master cyclinder, booster, and the abs/dsc units are deep in there. This is supposed to drain somehow... past the fender liner and through the bottom of the car. The DME itself is fine, it sits high enough, but the compartment filled up with enough water to get past the firewall grommets and leak down the driver's footwell.

Drewfus2101: During heavy rain or with a hose on the windshield peer at the bottom of this compartment between the booster/dme box/brake lines... you may see standing water there. Even if your drains aren't clogged, with heavy enough rain or enough water it may back up and enter the cabin and result in wet footwell/carpet.

dmax: Replaced the cowl during my troubleshooting. Water comes down the windshield, hits the cowl. The cowl drains left and right through the engine bay... on the driver's side this water enters this booster compartment and is supposed to leave out from under the car... somehow. I don't think the two bins are symmetrical as the drug bin has some large holes that are unlikely to clog.
 
#11 ·
SeattleGraugrun03, a question about that drain you unplugged under the DME, where does the water go that comes out this drain? I think my drain is not clogged but I always have water leaking from my front drivers side jack lifting mount. So water is building up behind the door sill trim panel, is it possible that water from this drain is some how leaking in such a manner that it comes behind the door sill trim panel? There is always a puddle of water under that jack lifting mount, after rainy days it increases :hmm: I never had a drop of water inside the car though, so the water is traveling a route on the outside of all water barriers/seals.
 
#12 ·
You have drains coming down a,b, and c pillars as far as I know...maybe just A and C pillars. From the sunroof drains for one, but also, the engine compartment drains (by hood plungers) also runs right behind wheel well...in the front corner of rocker.

Water under rocker isn't an issue so much, but if it's dripping when it hasn't rained, then that might mean that the drain holes are clogged. There's a little gap between the wheel well lining and the rocker. On my e36 I used to rinse out the rockers, but haven't yet on e46...but if it remains an issue for you, you could at least have a look in it (I think) by lifting up the wheel well lining a bit.

From your description, vigil, I'm not sure you have an issue...the jack pad snaps into the rocker and I'm sure it's not a water tight fit...the rocker is made to drain.
 
#13 ·
thanks dmax, that's comforting :) I'll have a look behind the wheel well lining soon.
 
#14 ·
drains

If you peel back the wheel well liner on the driver's side you'll see the little drains that are supposed to drain the main dme/abs/etc compartment in the engine bay. It's like the edge of the panel was bent to form a little arch, and just wasn't welded to the wheel arch, you'll see what I mean. In the liner itself is a little bump that's been molded in where this drain is so that water can drain along the liner and out of the bottom of the car. My final solution was to make a flap in the liner that I can easily access to stick a piece of wire/screwdriver in that drain to keep things clear.... The liner itself was already pretty beat up, so I just cut an access flat and secured it with zipties so I can get at the drains if I ever need to again. So far no more water in the car and the compartment doesn't have standing water in it after a rainy day.
 
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