No. This is a fairly new engine. 6500-7000 miles on it. Problem didn't start until mile 3000 or so (but thinking it was caused by the synthetic oil I went to conventional and it was still there). When I took the valve cover off today it still looked like a new engine (everything so clean and shiny).

As far as anti-drainback valve...I dunno, I just use the Mercedes-Benz branded filters. It uses the typical German filter element in a fixed housing style filter, not the spin-on stuff.