Good day Gents,
As Benzina mentioned I also had that issue with my Brera V6. It happened the same day I filled petrol at a dodgy pump, since I let the car go way too far into reserve. Might have been just the issue of letting it go into reserve too many times, but ok. Lesson learnt, I now fill up as soon as I hit half, worst case, preferably before
But yes I decided to take the tank out. Upon first removal of the pump I saw what looked like fine sand at the bottom of the tank. Not a massive amount mind you, but I suppose most of the crud ended up blocking the filter. It is one hell of a mission though. According to ELearn you need to remove the rear differential housing, but that is not necessary for in case you plan on following that route. Removing the exhaust sections, prop shaft, and disconnecting the various attachments are enough. The o-rings on the tank filler section tore on mine upon removal, so had to look for a replacement. It is a tight squeeze past the diff housing / prop shaft attachment point, but it will clear.
I was quite disappointed when flushing it out though. As you will see the tank has a large, centre-indented channel allowing for prop shaft clearance. Most if not all of the crud was collected on the pump side, since the other "section" of the tank only fills up above a certain level in the first "chamber". So I can almost guarantee that if you clean the tank using the pump opening, you should be able to collect and wipe off/out all the dirty bits.
As to compatibility, there were two part numbers for the pumps. One for the Q4 tank, and one for the front wheel drive tank. The only difference I can imagine them having is the addition of the Venturi tubing on the Q4 version, which is essentially a pipe from the main pump housing that is connected to the venturi tubes installed in the tank in the second chamber. I assume the FWD pump does not have this addition.
So unless you are sure that the tank is dirty on both ends, I would avoid removing the tank
Pump prop clearance.jpg