BMW M5 Forum and M6 Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
198 Posts
Discussion Starter #1
Well, I've been gone for 2 weeks and unfortunately my 6 had to be outside through a big rain storm. I get home and start her up and the cluster is dead. No lights, no gauges. Also the clock reset. I figure maybe low battery gremlins, so I drive around. I get home, still no dice.

I open up the trunk to look at the fuses and that's when I see it. There is water in the battery well. Not submerged, but maybe a half inch of water pooling at the back when the car is on a 30 degree upslope. So that sucks. I throw towels in there to soak it up and that brings us to now. Unfortunately, the car was parked on a downslope, so the water pooled near the front, not near the back by the battery.

Things that work:
Light control (headlights, turn signal, etc.)
ECU
SMG
iDrive (tested speakers and whatnot)

Things that do not work:
Cluster
OBC
Cruise Control

So I'm debating bringing it to my local indie or to my local dealer, I'm worried what might have shorted out and moreover worried about how water even got in there in the first place on a hard top. Before I head to the shop, is there anything I can check / hope for? Thanks guys!
 

·
Registered
Joined
·
3,244 Posts
...moreover worried about how water even got in there in the first place on a hard top. Before I head to the shop, is there anything I can check...
Take a look at the gaskets sealing the tail lights :lightbulb:
Some interior trunk trim must be removed, but the the taillights are only secured by a few screws (maybe nuts).
Not specific to the M6, but the foam gaskets sealing taillights dry out over time.

Unrelated to your current problem, but make sure the drains in the engine compartment are clear of leaves.
These drain the water from the black tray directly in front of the windshield into the front fenders. When blocked, water can enter the ventilation system and flood the interior.
 

·
Registered
Joined
·
759 Posts
I was thinking that since the car was parked nose down, you might also get water in through the trunk seal. Water coming down the rear window would pool around the trunk seal rather than simply run off via gravity when the car is level and/or nose high.
 

·
Registered
Joined
·
198 Posts
Discussion Starter #5
Thanks for the input guys! I'll check those taillight seals and I'll also investigate the trunk seals for any defects. If nothing looks obvious, I'll grab the hose and try and direct water to try and find the leak. I'm betting I'll still need the indie / dealer to figure what I've lost electronically, but I can at least get rid of the root cause search and save a few hours labor there.
 

·
Registered
Joined
·
198 Posts
Discussion Starter #6 (Edited)
Well, interesting result.

Got all the panels out of the trunk, unfortunately none were still damp to be a dead giveaway. I got the rest of the water out of the battery well, and then put it back together and the cluster was up again... So, everything that was broken is now functional again, I'm guessing as a side effect of unplugging the battery. Now begins the bigger game of whack a mole.

I ran water over the tail lights (not blasting, just running water from a hose), trying to direct it into the cracks and seals of it, seeming to simulate what would be worse than even the heaviest rainstorm I feel but did not detect any water via feel or paper towel. Perhaps I just didn't run it long enough, but I'll give it another go tomorrow when I have more light.

I also ran water down the rear window to give a the trunk seal a chance to reveal itself as the culprit, but that also did not work out.

The only thing I noticed was that the battery vent was disconnected when I took the battery out, but I don't think it's possible that that much water came up that tiny tube, if even any. I may just need to leave all the panels out of the trunk and check it after the next few rainstorms / rainy drives to see if I can't find a source.

Are any of those modules behind the rear drivers trunk panel responsible for the cluster and OBC? If so, I'll know which side to play closer attention to.
 

·
Registered
Joined
·
198 Posts
Discussion Starter #7
I'm beginning to think it's a seal on the rear window that has gone bad. I'm noticing now that the rear window is fogging up a lot whenever the car sits, leading me to wonder if it's water evaporating in that area. Also, I found this discoloration / possible beginnings of rust on both sides of the trunk as pictured below, linked because pictures are gigantic. Look at the area by the rear quarter panels.


Drivers Side

Passenger Side

I'm not sure what that spot on the insulation in the drivers side picture is. It's not damp, but it does look like something happened to it in the past.

Do the rear window seals go bad in 6s? The rubber still feels good, but the fact that:


  • water is getting on both sides of the trunk and into the battery well as well
  • There is that discoloration on both sides
  • Interior windows fogging up a lot
Make me wonder if it's water coming inside the car then going into the trunk.


My buddy got in the trunk as I was running water over the car, but we didn't actually see or feel any water coming in during that time, which was frustrating.
 

·
Registered
Joined
·
759 Posts
It sounds like you are doing a thorough diagnosis, and yet can't seem to positively locate a leak. Frustrating for sure. The telling thing to me is that your rear window is fogging. This is obviously too much moisture in the rear cabin. But without a source, I do not know what I would do next. How about the side window seals? Do the side windows drop when you open the doors, and reset when you close them?
 

·
Registered
Joined
·
198 Posts
Discussion Starter #10 (Edited)
Remove the battery and drill some drainage holes underneath. Problem solved
Heh, I wish. It's looking like it's barely starting to surface rust on the right side, so I want to seal this before any more water can get in.

It sounds like you are doing a thorough diagnosis, and yet can't seem to positively locate a leak. Frustrating for sure. The telling thing to me is that your rear window is fogging. This is obviously too much moisture in the rear cabin. But without a source, I do not know what I would do next. How about the side window seals? Do the side windows drop when you open the doors, and reset when you close them?
That was weirding me out too and I was thinking along the same lines of water getting in to the cabin and then seeping into the trunk. The windows definitely seal. I don't know how water might get in there though. I was thinking maybe C pillars from the gap at the back on either side of the "rails" on the roof, but putting a hose on that didn't produce anything meaningful. I don't know if I just need more water or if I'm on a wild goose chase with that.

Debating just taking it to the dealer near me since maybe with the volume of cars they see, they might know where some E63s get leaks.
 

·
Registered
Joined
·
16 Posts
Did you ever figure this out, as I seem to be having the same problem, and living in England it is more of an issue than Cali!
 
1 - 11 of 11 Posts
Top