Originally Posted by babymog

It can be done, I've had CAT and Detroit engines that had a single filter system. The nice part of the pre-filter (aka: secondary) in the older Mercedes is that it's clear, you can see the screen in it and tell if there's something amiss, similar to the Racor filters we used in our coaches. Buy a nice heated Racor with water-in-filter warning system and clear bowl and you need nothing else, but it is overkill for a car that burns good clean pump diesel.