Anyone look at their water hardlines (arrow in pic) that feed the heat-exchanger under the oil filter ? You would not normally see these, but I was under my car and had removed the heat shields prior to removing the transmission. It looks like road salt from our NE winters has started to eat the pipes away. I'll probably remove these and give them a coat of POR15 before putting everything back together, as I hope not to see them again in the near future (too much work!).
Ian
'02 MCS, somewhat rusty after 5 NE winters

 

Cleaning them up & hitting them with some POR15 would be what I'd do too. I doubt that is more than surface rust.

 

That's the bad thing about them NE cars. All that salt from winter does a number on them.

 

Uhg, really dont want to think about it...

 

There is also one that runs over top of tranny to water pump you had better check it as mine was almost gone thru. Easy to replace with tranny out, but you have to loosen the intake manifold.
Part no. 11537510760
http://www.realoem.com/bmw/showparts...00&hg=11&fg=35