This article describes the restoration process of the fuel tank.

The fuel tank on the Alfa 33 models is made of steel which means that they are prone to rust. Fuel over years develops moisture (condensation coming from temperature variations) which is accumulated on the tank bottom slowly resulting in corrosion. Someday this corrosion will eat away metal and fuel will leak out.

Failing tanks on the Alfa 33 that is owned from brand new since 1991 started within the early months of ownership. 

Within 1.5 years since new, two new tanks were replaced under warranty as the internal diaphragms broke and the splashing waves of petrol flowing inside could be heard while driving. After almost a decade, problems started to arise again Spring 2004 about 30 lt of petrol dripped on the floor of my home's garage; I decided then to have the tank repaired by a radiator shop. The shop owner patched the tank on the corroded place and installed a drain plug so as to be able to drain fuel should any need arise. Within 20 hrs after the repari the tank leaked again from another weak spot around the seams (losing again around 50 lt of petrol). Frustrated again, I decided to purchase a new tank; Luckily I got one of the last new tanks Alfa was able to supply as these nowdays are nearly impossible to get new. Everything was smooth until Spring 2008 when the tank leaked from a spot weld.

This time I decided to solve the tank issue for good. A very promising product advertised on the web and used by many car enthusiasts claims to seal the tank internals and fight corrosion on metal tanks. This is POR15 Fuel Tank Sealer and the website is http://www.por15.com.