[Kran1um]

I had a line of goo drip down the center of my rear bumper cover a few weeks ago. I figured it was tree sap or something flung back there maybe by the aero vacuum behind the cover because it was not on the trunk lid, only the top and rear facing sides of the bumper cover. It was very hard to get off of there.

Fast forward to a few days ago and the line of goo is back! This time it must have been "fresh" and it was very fluid, much more like a gear oil than a sap. Scared me that my rear dif might be unwell but it is dry as a bone under there thankfully.

Assuming this must not have been a coincidence, I hit google and the forums and it appears to be a pretty well known issue with BMWs (https://www.2addicts.com/forums/show...ight=Cosmoline).

So my question is has anyone else seen this on their CS, especially in the Southwestern States or warm climates? It seems this stuff basically melts at what would be room temperature here in Arizona. The search results seem to indicate that this isn't super widespread, I wonder if this just means they put too much of the stuff in the skin of my trunk lid. I determined that it was leaking from a breather hole that's right in the center of the trunk lid just rearward of the latch mechanism.

The good news is that it is easy to clean when it is fresh and oily. The bad news is I saw some posts that said it had leaked out of their car for 3-5 YEARS

I didn't take a photo but it basically looks like this.

[Wah]

Not on my M2, but my old X5 used to poop out the back like that and I got it used, so it was probably 5-6 years old by the time I sold it.

[aroundelway]

Yep happens to me.

[Kran1um]

Originally Posted by aroundelway

Yep happens to me.

Just from the trunk as well? It seems this can come from fenders, hoods (not the CS carbon hood thankfully), doors, etc. Maybe if I park in the sun on a 115 degree day I can melt it all out

[6CylindersEveryDay]

Weight savings over time.

[allinon72]

Never had an issue on the exterior but it poured out of the door drains of my F97. No issue on my X5 or M2C.

[Kran1um]

Originally Posted by allinon72

Never had an issue on the exterior but it poured out of the door drains of my F97. No issue on my X5 or M2C.

Thanks for chiming in, my brother in law has had maybe 5 BMWs, mostly suvs, and he'd never heard of this. It really does seem like it is random enough that it might be as simple as some cars getting too much applied at the factory.

[Golden3ye]

I would be so sad if this was happening to my car. These things are too expensive to be leaking mystery fluid from random spots.

I had an old Mitsubishi eclipse that would do this in the doors, and it would get all over the door sills. It happened every summer for the entire time I owned that car. Maybe like 7-8 years