Hi, I own a 2009 ML280 CDI sport ( W164?) with the 3.0 litre V6 engine. My problem is that recently the glow plug light on the dashboard stays lit for about 40 seconds after the engine has started. This seems to indicate a faulty glow plug (s). Can anyone point me in the right direction as to where the glow plugs are on this engine and how easy/ difficult they are to change please? I have taken off the plastic cover and recognize the 2 common rails feeding each cylinder bank and the fuel filter in the middle, but cannot see anything remotely like a glow plug or its electrical cable attachment. Any suggestions / help would be gratefully appreciated. Thanks in advance, Jimboom.