Ok here is the deal... I had an extrnal head gasket leak on this car a
month ago and had a friend change the head gasket everything was fine.
I put about 700 miles on the car in 3 weeks or so with no problems.
The car sat for a week without being run. I took it about 70 miles on
the highway (it has never gotten hot after the gasket change) when I
took it out the next day I noticed it was running ruff at idle and low
speeds but fine at high speeds. I figured it was just the  fuel filter
or bad gas maybe. well today I checked my oil and noticed a white
greese like goop on the top of the dip stick and a little in the neck
of the oil filler tube (but only at the very top).  do I now have an
internal leak in my head gasket? I have not lost any coolent. could
something else cause this white goop? how can I test? I don't mind
doing the work myself and feel confident that I can.  just need to be
put in the right direction...    

thanks in advance
Jim