Valve adjustments are not that big of a deal to do.
I use to have VW`s and think they are every 12,000 miles
And my 82 Datsun with the SD-22 Nissan Diesel engine, is every 12,000 mi.
the Datsun and the VW are similar in the adjustments. the mercedes is a little more complicated, but very doable.
The hardest part on the mercedes is getting the valve cover on/off. always
hangs up on something, then the gasket falls off. about the 3rd or 4th time, I win.
Maybe since my timing chain fiasco Iam a little more on edge, checking, and bonding with my baby
.
Not that big of deal, just do it.
Charlie