Filling up gas tank all the way up, harmful?

Question

I know its bad to ride on Empty alot, but is it also bad to constantly fill your tank all the way up to the top. I heard someone talking yesterday and said that it was harmful to do so, but did not hear why. Any comments?

Answer 1

No, other than the dent it puts in your wallet, there is no reason why a full tank would be harmful to any part of your car. Actually, if your cars fuel system has a return line from the fuel pump, this return line is putting hot fuel back into your tank... so if you have a full tank, the temperature of the fuel in the tank would be lower than if you had relatively little fuel in the tank. Colder fuel makes more power.

Answer 2

If you fill the tank to the point when gass is spilling out from the pipe, yes, this is not great. You have to allow a bit of space for the change in temperature while the car sits over night etc, if you fill it right to the top, then this expansion has no where to go put spill out.
If you are in the middle of a long trip, or are driving the car a few miles after it is filled, then this is not so much of a problem. Best practice is to fill it until the nozzel "pops off" on its own, then round it u to the nearest dollar value, not more, and you will still have an air space to allow for the expansion of the gas due to to the temperature changes.
As for the constantly running on empty, yes, this is not a great thing to do, as it MAY cause sediment and other debris in the bottom of the tank to be put in the fuel line and to the engine. There is a fine mesh filter inside the tank to prevent this kind of problem as well as to prevent water from getting into the lines and freezing or causing engine problems.
You should have your fuel filter changed once per year.

Answer 3

I've never heard of that. I heard that it is bad to ride on Empty. You should always fill your tank when at about a 1/4 of a tank. This won't alow the siting dirt or anything on the bottom of the tank to flow through the gas pipes. Though it makes no sense because when you fill the tank doesn't it mix in to the gas anyway and goes in to the gas line anyway.

Answer 4

Best practice is to run it from full to nearly empty at least every few fill ups. Keeping your tank full is a very good way to prevent condensation from building up and avoid walking. However, gas does have a shelf-life, so you want to run it low and fill with fresh gas in order to keep it the gas fresh. Also, from time to time adding a fuel system treatment to your tank will help to keep your fuel system clean and help reduce/remove any condensation that does build up.
As far as leaving room for expansion goes, your tank is built with that in mind. As long as you do not try and put more gas in once the filler nozzle shuts off your ok. Also, you gas cap is built to release any excess vapor. When the fuel expands due to heat, it does so in the form of vapor.

Answer 5

Fill er up, just leave a little space for expansion. The full tank allows less room for evaporation of the gas which leaves a varnish which in turn causes problems with the carb. or injector system. Evaporated gas is a waste of your money. A less than full tank has more air in it. Air has moisture which will condense in the tank to form water....more problems.
A full tank is a better tank.

Answer 6

Never heard it was harmful to fill tank all the way, it is not necessary to "top off" tank after pump shuts off.

Answer 7

Gasoline tends to expand and could spill out if there is no space left in the tank. So you should leave some space for air. There is a fire or explosion risk if gas is spilling out of your tank. Mostly what everyone else told you.

Answer 8

The only way I think it is harmful would be that it is harmful to the environment from over filling spills.

Answer 9

just fill it until the pump clicks twice, it is vented it can't have liquid in it.