A sample from the products for the Oil Tank include: Bolt, With Washer(55k), Hose, Body, Cap, Tank, Oil.
The most reasonably priced component used on the Ye50 1993 4fx1 England 234fx-310e1 Oil Tank is the Bolt, With Washer(55k).
In this schematic the "Bolt, With Washer(55k)" is used most often.