Mercedes-Benz E420 Forum : “lifter noise”

i have changed oil , filter (mercedes)several times used synthetic and regular oil

its common with the m117 engine..they use plastic oiler tubes and sometimes the plug on the end of them pop
out and thats what causes the ticking noise..i would replace them with metal ones if you can find them, if not just
replace the oiler tube with the missing plug and you'll be all set!

Can this noise cause damamge to your engine?

no, since the originals are made out of plastic they get chewed up  and ground down but it's not something i recommend keeping..you
should switch to the metal oilers..it will fix the ticking noise and last much longer