There is some kind of lifter-type ticking noise there. Fortunately the hood insulation is good enough that I only hear it when I open the hood.

Question: what's the best oil sludge flush? Is there an MB part, or is the Pep Boys Special good enough?

Also, since Chevron/Texaco ceded this territory to other oil comapnies, Techron is off the list. Any other alternatives for top end cleaning not requiring the removal of 16 plugs?