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      04-01-2024, 07:04 PM   #20
kk7ds
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Drives: 2006 Z4 3.0si
Join Date: Oct 2018
Location: Portland, OR

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Quote:
Originally Posted by MarinerZ4C View Post
In addition to the drain for the fresh air vent pointed out by Grannyknot, there is another entry point under the hood, center of the firewall. It's the "scuttle drain", which is supposed to be fitted with P/N 64116915666 (Drain grommet, condensation water). It's not really for 'condensation', but for any water that isn't drained from the false firewall area by the two side drains.

This valved grommet is a bottle-neck that can accumulate leaves and other debris, plug up, and cause corrosion. Many owners or their mechanics remove the grommet/drain tube to prevent that. If yours is no longer fitted, you'll likely not even notice the 1.5 inch / 37mm hole in the overhang of your false firewall. My car came with the grommet missing. You will notice it if you have to remove and replace the trim molding below and in front of the windshield. With no grommet in place, it's a direct doorway for a mouse. I have the part, but I have not yet replaced it.
Okay, so I believe you're right about this. With all the center console stuff removed, I see the top of this where it enters the cabin (item 8 in the diagram). If I stick my finger in the hole while driving, I feel obviously hot engine air very actively through the hole, which changes with driving speed.

Looking under the car, I can't for the life of me see how/where this neck would have been easily removed by anyone as it seems like it must drop right on top of the transmission (which is probably the reason for the S-shaped offset). Am I not looking hard enough or is it way too difficult to actually access? I'd love to not only confirm that it's missing but also replace it. We don't drive this in the off-season so no chance of it getting plugged.

If I can't easily access it, I was thinking maybe just some stainless mesh cut almost to size and pushed down (like the strainer in a faucet) into the hole to prevent them from chewing through.
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