could anyone please tell what this green foam is in my engine? I have a 78
TII with a 2.0L FI. My bus runs great and has good power, but I noticed
the  last time that I checked my oil that there was this green, slimy foam
on the oil filler cap and in the oil breather. I have an moderate oil leak
from the starter if that helps. Also is there any way to tell if you have a
collapsed lifter (hyd) ? I have this very light, erratic qlick sound, that
almost sounds like tapping, but it disappears past idle. Any insight would
be geatly appreciated. Thanks.

Regards,
 Dave
sidote@mbcl.rutgers.edu