Carbon9

When my car sits for several hours or overnight, most of the oil must drain out of the filter as I hear an oil starved clatter noise till pressure builds up (one or two seconds) after startup.

Aren't the filters supposed to have a ADBV of some sort? (anti-drain-back-valve)

Filters that are mounted top down and level with pan don't have this problem, but my filter is on top of the engine with bottom down positioning..

levelr123g

if you have an old 2002 c230 with the 2.3, this was a common problem. my take on it is a hydraulic cam chain tensioner that loses prime while sitting overnight. WHO KNOWS!