Unless you have had some really bad gasoline, or the car was sitting with gas in the tank for a prolonged
(very long) period of time, there should be no need to clean the inside of the tank. The tank has a bladder, the construction of which I am unsure but it's pliable, like rubber, and nothing should stick to the tank like it would to the steel tanks. Today's gasolines don't break down into a varnish-like substance anymore unless you're talking a long, long, period of time. It used to be only a matter of months when the gasoline would go bad, and varnishes would form. Gasoline still only has a recommended shelf-life of about six to eight months at any rate.
If you do want to drain the tank, it would be a lot easier, and almost just as fast, to simply disconnect the inline fuel filter and let the gasoline drain that way. You should be able to get just about all of it that way.
As for cleaning the tank before performing any hot work on it, please keep safety always a first priority. I wonder how many people are aware that RFG can be more volatile than normal gasoline.
Although I'm sure we all know
all gasoline is very flammable and it must be handled and stored with extreme care. However, under certain exceptional circumstances, RFG (Reformulated Gasoline) may present a hazard which conventional gasoline does not.
Typically, the gasoline/air mixture in a vapor space -- the space above the liquid in a fuel tank or storage container -- will not burn at normal ambient conditions because too little air (oxygen) is present. When the tank/container is filled with gasoline, much of the air is displaced by gasoline vapor. Because summer RFG has a lower vapor pressure, it will form less vapor and displace less air under the same circumstances. When summer RFG is handled at very cold temperatures -- which might occur in certain areas during the spring transition period -- it will form even less vapor. At temperatures below 20°F, the gasoline/air mixture in the vapor space above a lower-vapor-pressure summer RFG could become flammable. This creates the risk of fire if a source of ignition is present.
Anyone who handles gasoline should be aware of, and consistently and carefully follow, current safety guidelines. This includes keeping sources of ignition away from gasoline and gasoline away from sources of ignition. While this precaution applies to all gasolines at all temperatures, the above explanation shows that it is especially important for RFG at low temperatures. In addition, if you store RFG purchased in the spring or summer at very cold temperatures, it may be prudent to keep the container as full as possible to minimize the vapor space.
Safety first!
:cry
