2009 - W211 E220 CDi - is this noise normal?

[Mintyfresh77]

Engine is OM646 Evo 2.2 with a full history and 122k covered.

Is the noise in the attached video normal prior to cranking? When you turn the ignition on this process starts and lasts 20-30 seconds. My gut feeling is that it's pressurising the fuel rail and perhaps purging air. The noise comes from the black slatted plastic pipe fitting near the 4th injector pipe seen in the video but it strikes me as odd that this lasts so long and what a bizarre noise!!??

Youtube - Strange Noise

Thanks in advance

 

[Tsb1983]

Don’t recall having it on my 320cdi but it was a long time ago - so maybe a fault.

 

[BlackC55]

That sounds like a fuel flow noise possibly. Use a screwdriver to your ear to pin point it.

 

[TeddyRuxpin]

Make sure you get the screwdriver the right way around

 

[Mintyfresh77]

That sounds like a fuel flow noise possibly. Use a screwdriver to your ear to pin point it.

Make sure you get the screwdriver the right way around

 

[Mintyfresh77]

Just to wrap this one up. As far as I can gather this sound is perfectly normal on the late OM646 Delphi Fuel systems. The problem I was having with the car is fully resolved and the sound remains; it is essentially the system pressurising but because of the venturi part of the system is creates an this noise prior to firing.