92 nissan maxima sounds like a diesel - help!

my 92 Nissan Maxima sounds like a diesel - only when idling. Sounds like valves? My mechanic says its the hydraulic lifter. I used 60% Lucas at my last oil change and the rest oil. The noise went away for a week. The noise is a tapping - does not affect performance but is annoying and sounds bad. Plus I want to sell the car since I am moving overseas. What about Rislone Engine Treatment?

I’m not sure how those kind of additives works, but if you have a bad lifter(s), that needs to be replaced either way.

I heard that replacing the lifter doesnt really do much. ??