I have always filled up my gas tank in all of my cars cos long time ago there was a myth about unused top portion of gas tanks getting rusty if its not filled up regularly. Is this still true with the new MINI?

I am thinking of filling up to a half tank for everyday use and fill it up all the way only on long trips.

 

Filling the tank keeps condensation down (water in the gas) but since the MINI's tank is made of plastic, rust won't be an issue.

I don't understand your strategy (1/2 tank unless a long trip), why would you do this?

 

Less weight for the mountain

 

gas is heavy!

 

The way gas prices are rising, he might be better off filling up each time. By the time he's done with a half tank, price will have gone up. Best to lock in the lower prices for a longer period of time.

 

Wow, plastic... would have never guessed that. Thanks! Can you elaborate on condensation. If I fill up half a tank and use it up in a month will it be a problem?

Yes, like everyone had guessed that strategy is to keep the car lighter. I think there is a difference. Well it's almost a month since my last tank fill and I think I can go another month without filling. So frequency of gas stops is not a concern.

 

I have noticed German cars handle better when the gas tank is filled.
(Or at least rides better, the MINI included)

Maybe its just my imagination.

 

You are only talking about 5 gals or so of weight (30-35 lbs).....not going to make any real performance gains and the fact that it takes that long to go thru the gas I would say keep it filled up instead of half full. Less chance for the condensation ( that will be absorbed by the ethanol in the tank) to cause problems.

 

The condensation is from the air in the empty part of your tank. When the air cools, say at night, water vapor in the air will condense on the tank walls and then run down to the bottom of the tank (because the water is heavier than the gasoline). The ethanol in the gasoline will then absorb some of the water, which your engine will then try to burn. In small amounts probably not a serious problem, but it has been known to damage fuel pumps and injectors. In extreme cases, enough water can collect in the tank to be picked up by the fuel pump. Despite gazillions of research dollars, our MINIs are not yet able to run on water. By keeping the tank full of fuel, there is less air in the tank and thus less condensation.

 

Great information guys. Thank you!

Yes, 35 Lbs is insignificant for street fun.