My employees say you get better gas mileage when you fill up with half a tank.Does it matter?

Question

I say it doesn't matter. Who is right?

Answer 1

Not only will it not make any difference in your gas mileage, but a full tank provides much better cooling for your in-tank fuel pump. Since a new fuel pump repair costs around $700, it's in your best interests to keep the tank full.

Rick

I'm a retired ASE Master/L-1 Technician. I still keep current with the latest automotive technology. Visit my blog for cool articles and TSB's: http://free-auto-repair-advice.blogspot.com

Answer 2

I would say it does. My bro drives his truck to work and wastes 15 bucks a day when he only fills it up once the gas reaches empty. Though when he fills it up completely it last him over a week doing the same drive. 5x15=75 and his tank takes 80 dollars to fill. So if he filled his tank it should last him 5 days since that is how it is when he adds 15 dollars at a time. Though we have done a little test on it before only doing the same route he does and it lasted him 8 days on a full tank.

Answer 3

No, it doesn't matter. As another person answered, the extra gas will keep the fuel pump running cooler.

The gas mileage depends on the flow of gas, not how much is in the tank.

Keep your eye on those employees. lol

good luck..

Answer 4

You may get a little better gas mileage just because less weight = better gas mileage. But it would be so small it would be negligible. 1 gallon = 8lbs

Answer 5

I think they are fooling themselves. It's the shape of the fuel tank that is fooling them. My Dodge Ram goes 600 Km on the first ½ tank, then 200 km on the lower ½ all due to the shape of the tank.

Answer 6

gas at normal temperature vaporises, and as such with a full tanks there is less room for vaporization, with 1/2 tank and less more of it becomes vapor, and that is a loss. Next if you fill it when it is hot out, you get less in than if you fill it when it is cool out for the same reason