Should I wait until my tank is on empty to fill up?

    Published: 06-16-2009
    Views: 42,656
    Fuel economy expert David Rizzo discusses if you should wait until the tank is on Empty to fill up.

    Host: Should I wait until my tank is on Empty to fill up?

    David Rizzo: Never wait until the tank is on Empty. At best you want it about half full. There are many reason for this. First of all in the summer, again we are talking about vapor and that vapor you cannot burn it, you need liquid in your tank. So, if you are driving around and parking your car on an empty, on a hot night that vapor escapes. Yes, cars have evaporative emission control systems that recapture the fumes in a carbon canister and put it back in in the morning, but you are still losing it, especially if your gas cap isn't really secure. So, keep you tank topped off, especially overnight. Another reason why you want to keep your tank at least half full when you go to the gas station is with new cars, the fuel pumps are located in the gas tank, and they cool themselves with the liquid fuel. So, if you run on empty, you are running the risk of burning out your fuel pump. If you have a older car, the fuel pump of course is located on the engine block but even still the older tanks rust. They collect all these rust particles that sit in the bottom. If you run your tank empty before you fill it, again you are going to create some turbulence, those rust particles will get in the gas, they will get in your fuel injectors in your carburetor and create problems that decrease your gas mileage. So, always fill up when you are at least about half maybe be one-third tank, no more, no less.