Hello All,
I have searched and can't find any previous information. I have a ML350 W163 199K 2004. Recently changed oil (500Miles ago) and went to check oil after a ride and found this white milky substance under cap. Doesn't seem to be burning much oil although some, and can't see there is any apparent coolant loss. Any ideas what this is? I did just get a code for EGR P2001 P0400. I doubt the EGR has ever been off the car. So that is understood. But no other issues. Imagine the entire cap where the letters are covered in this white froth you see on the outside edges.

White froth around edge. What is it? Also was where cap numbers are thin coat.

Thanks, John

 

That white gook is not a worry but indicates that it is caused by multiple short trips. Leave the gook on the cap and take it for a 20 min ride on the hwy. and you will see that it has disappeared.

 

Thanks. I'll try that.
JH

 

Normal, it's condensation.