A forum member who goes by Lebenz (Tracy?), posted in this thread:

http://www.peachparts.com/shopforum/showthread.php?threadid=49326

... that if you see sludge in a valve cover of an M119 (same engine family as yours), don't buy it.

Perhaps he can enlighten you on what's going on.

Click the email button at the bottom of his post to direct a message to him.

Sixto
91 300SE
87 300SDL
83 300SD