2009 Ducato 2.3lt "leaking fuel filter"

Dorset Driver was the expert on this subject but he no longer posts on this forum.  In November 2012 he managed to get DVSA / VOSA to carryout a detailed investigation into what was then a constant problem.  It affected my 2009 Fiat based van at the time.  But the only thing I can only remember is that you must use only actual Fiat parts when you replace the filter and seals in the housing.  For some reason the housing just won't accept aftermarket parts.  I occasionally see Dorset Diver on the Motorhome Fun forum so maybe you could post your question there.  

The Fiat Forum has a Ducato section which is useful for this type of query.

https://www.fiatforum.com/forums/ducato.108/

The issue of diesel fuel leaks from the fuel filter housing are extremely well documented on most of the motorhome forums and a google search should bring up several days reading material !

The issue seems to be if you just try to change the fuel filter rather than the whole canister, then if it is tightened incorrectly it leaks .

Laser sell a special tool to help tighten it up correctly......

But most people seem to advocate buying a replacement whole canister including the new filter. A search of the famous auction site should bring up plenty of choice...

You seem to be saying that even changing the whole unit you are still having leaks?