Cowl Drainage

[dcover7]

My elephant trunk was plugged up, so while I was replacing that I decided to check how the cowl drains. I took off the cowl grills and poured water into them. On the drivers side it seems as though everything drained out the front rocker. However, on the passenger side it drained out the rocker and at the corner of the battery tray (look at picture attached). Is that why the battery tray rusts?

I removed the battery and found a decent amount of surface rust on the tray. I'll be grinding that away shortly. From what I could tell without being able to fully remove the firewall insulation behind the battery, the firewall is rust free.

I cant get those screws out that attach the insulation to the firewall. They turn but wont come out and I've already ripped some of the insulation trying to work it out. Any insight on how to pop those out? I see that they're attached to the inside of the cowl (2cd pic attached). Thanks!

[tomstin]

As I recall they are plastic nuts. Are the nuts just spinning? If so, cut them off with a dremel or something similar. If the studs are spinning, different problem but cut the nuts off, you can order new ones from BMW then decide if you need to weld the studs or jbweld them in place. They carry no real load.

[dcover7]

Thanks for the reply, I’ll give it a shot. So is water supposed to spill out of that back corner of the battery tray from the cowl? Seems like an odd drainage point

[Zambuzan]

I've had a similar problem where water was entering the battery tray area under the hood (although thankfully mine is a coupe so rear-battery for me). The water was seeping through the cowl area and through the rubber firewall by way of the plastic nuts. All I did was put some black silicone to fill the holes, but some water still seeps through. Oh well. I don't feeling like messing with it anymore lol.

My main problem, however, was water entering the battery tray area through a crack between the fender and the body of the car. This crack is located under the hood seal. For a while, I had my car on jacks with the front of the car a lot higher than the rear, and I found water getting in the passenger-side cabin through the air conditioning lines because this grommet (64531372609) failed.

Long story short, check all of your seals and potential water-entering areas!
Good luck.

[Mpolito3355]

I decided to check how the cowl drains.

too much time on your hands ^^^ lol jk jk

Thanks for the reply, IÂ’ll give it a shot. So is water supposed to spill out of that back corner of the battery tray from the cowl? Seems like an odd drainage point

i thought the same thing i never noticed that but seems like a dumb place for the water to drain ..... maybe you can rig another drain tube to carry the water through a new drain .....

if you do it post pictures