So 'Scuttlegate' is still happening !. This has been a long standing problem with Ducato's since the X250 first started in 2006/7
Part of the problem could be broken mounting clips when the scuttle was fitted, or a warped scuttle. Either way water can get into the engine compartment between the windscreen and scuttle and at best leave puddles in the area between the cams, or at worst get into the electrics.
I have a 2007 Ducato which had a scuttle you could put your fingers behind when new. FIAT not interested, there solution, spray 'Waxoyl' onto the top of the engine, so did a 'fix' myself.
Firstly you need at least a day (preferably two) to do the job, and again preferably under cover if possible, or choose a couple of dry warm days.
Process is:
1, Remove bonnet. Not too difficult, four bolts but heavy so might need two people to avoid damage to yourself or the van
2. Remove both wiper arms having remembered to leave them in the 'park' position.
3. Remove the scuttle. Not sure with the newer model but the 2007 was in two parts. From memory two screws near the middle, and two near the ends.
Now pull the scuttle outwards to disconnect from the mounting clips. Chances are either some missing, broken, or distorted. If any are, try to get replacements.
4. Give the bottom of the windscreen and scuttle a good clean.
5. Now the difficult bit. I used 'Sikaflex 521' because I had some, but other flexible sealer/adhesives will do. Preferably do not use Silicon type sealants as
they can be corrosive and will fail faster than Sikaflex type adhesives.
Make sure all clips are in place, then run a thick bead of sealant along the top (windscreen) side of the scuttle, basically on the back of the more flexible section.
Put the scuttle back and make sure the clips click into place and sealant oozes out of the top (windscreen side) of the scuttle. Keep pressure on the scuttle until the adhesive has dried. Sikaflex takes about 30 minutes but I used some bits of wood to leave it for a couple of hours to dry.
6. Once you are happy the adhesive has dried, cut of the excess from the top of the scuttle. Carefull you do not damage the windscreen.
7. Put the screws, windscreen wipers, bonnet back.
Scuttle should now be well sealed and not leak at all if it has been done correctly. As an add on, it might be worth fitting extra drain holes on either end of the scuttle as if parked on a sideways slope, water can overtop the scuttle and get past the scuttle/bonnet into th engine compartment. There was a kit on FleaBay for this, but I did it myself.
Pro's, Did the mod in 2009 and not had a drop of water come into the engine compartment since.
Con's, If you have to replace the windscreen it has to be done again.