My lower level says 'MAX' - don't yer just love Italians ....and if you use 10w40 or thinner on a tired engine, in summer it'll burn it like a 2 stroke!
Sounds like the tank drain pipe is blocked either in the tank or in the tube from under the tank. From memory its the the metal pipe thats connected via rubber hose to the fill cap mount, might be worth a quick test to check the drain works when your replacing the seals.
