Noisy tappet (valve gear)
 

Why does the my dear old 190E have noisy tappets(valve gear, noteably just one)after every oil change.For the fist 500 miles after every oil & filter change (GENUINE MERCEDES PARTS)For the first 10 miles after startup the valve gear is very noisy.After that she settles down to her normal quiet self(It HAS ONLY DONE 168000 MILES)My last one did 326000 miles.Yes I have tried all! the engine flush treatments.Qestion why only after an oil change and why only for a few hundred miles till she settles down.