The following mainly pertains to the M111.975 Kompressor engines. There has been very little written here on Club202 about the peculiarities of the EGR system for the Kompressor models and how it works. I found the following thread that shows how to clean it and what to expect. In addition, there are links to other threads which discuss more of the issues involved with this system that is a bit different from the normally aspirated 1.8 through 2.3L engines. I believe you have to join the group to view the thread, but the whole forum there is a great resource and for people who are needing help figuring this system out, it is worth signing up:

http://forums.mercedesclub.org.uk/sh...ad.php?t=34036


Keywords to help others during future searches:
EGR
cleaning
plugged
clogged
valve
oil in or on air filter
oil on MAF