Are hydraulic lifters, cam shafts, push rods, and valves consider to be
"internally lubricated" parts of the engine?  The reason I am asking is that
I've noticed that my '99 E320 (with 91K miles) has a slight tap when idling.
I assume that this is due to one of the items I mentioned above (lifters or
camshaft being my first guess) and I still have the car covered under a
Starmark warranty that states that "internally lubricated" engine parts are
covered.  So before I take the car into the dealership I wanted to verify my
belief that these are indeed internally lubricated.

Josh