I was asking for a reason - I don't have MB diesel experience - but work on VW diesel all the time. I know that on the VW diesel when you change the fuel filter you sometimes get an air lock and you have to prime the system to get the fuel going again. Before you start changing the filter - do a search on this site for any problems with priming the system - just in case you should need to do it. Better to be armed with all prossible information before starting and save a lot of cussing if something does not go right. Good luck and let us know how you make out!!