Hi Steve same engine as in my ML270, which I had to dig apart to do the flippin' swirl flaps (story with pics of my mod here
https://forums.mercedesclub.org.uk/index.php?threads/ml270-swirl-flap-question.174580/ )
I'm finding that the Bosch CP1 injection pump has six o-rings that aren't bio-proof - three of those are the big ones that each of the three heads clamps down on to, to seal with the pump body. Consequently (every 6 months) it starts leaking bio onto the multi-v belt which then flings the bio around the engine bay, primarily onto (in my car) the PS pump fluid feed and various suspension rubbers - which then also fail.
I contacted diesel bob about finding pump seals that are actually Viton but with no response. I've rebuilt the pump several times with the FLAG kit from Germany and others with no long-term success. I have three CP1 pumps in rotation - they are very easy to swap out; remove the vacuum pump (two bolts) then three bolts for the IP, a fuel pipe clamp and a high pressure union and it's out.
The other thing to note is that the fuel hoses themselves (the black ones) have a viton inner, mesh strengthener, and then an outer that is not bio proof. So wipe down and wash off any bio spills in the engine bay (particularly if changing a fuel filter) or these pipes will turn to cheese, allowing you to flake off the outer down to the protective mesh around the viton inner...
That aside it's actually a great engine for bio; the fuel return is cooled to the tank and there is a cunning EGR-flow fuel warmer before the filter which eliminates waxing in cold weather - really makes it a year-round bio car if you can get over the leaky injection pump. One day I'll just measure the o-rings and replace them with ordinary viton ones...
