Ok, it’s not that bad, but at a gas station I went to recently (I believe it was a Texaco) there was a pretty big sign on the gas pump that said something close to:
Help stop air pollution
Don't overfill your tank!
It's your air too! :)
(happy face theirs)
…the HELL are they talking about? If I spill a few drops, it’s not gonna affect the air in any measurable way, and I can’t imagine that topping off my tank is gonna screw with my catalytic converter (is it?). Or is their theory that if I only fill my tank partway with gas, I’ll drive less?
Is this just some stupid eco-gibberish, or am I causing the destruction of the whole ecosystem by putting that extra .23c worth of gas into the tank?
The gas expands after it warms. It’s cold in the ground.
I once worked at a diner by a gas station.
People would fill up, topping off, and then park at a slight upslope at the diner. The gas would soon be gushing out their fill tubes and stinking up the place through the open windows.
Now I have a factual reason why my husband should no longer torture me by jiggling the car to get that extra $.53 of gas into the tank. He’s under the impression that you get better mileage if you fill it to the brim.
When you’re the one waiting behind him for the pump, I’m the one on the floorboards. I think his personal record is 30 min for a 25 gal tank.
Gasoline and other organic solvents are not good for you in the sense that they cause cancer. Gasoline vapors, paint solvents etc, can be pretty bad for you. Especially if you work in a place where you breathe them all day.
I heard that if you overfill the tank, not only will the extra gasoline drip out, but in the process it damages the filter which normally traps gasoline vapor. I think it’s just a charcoal filter which absorbs the vapor, but if it degrades, vapor will continue to leak out of the tank.
Yes, you are referring to the carbon canister in the EEC (Evaporative Emission Control) system. If the tank is overfull, this filter can get saturated with gasoline, and gas vapors can leak into the atmosphere.
It’s a small thing on one car, very small. But the cumulative effect of it happening on many cars is large.
A simpler reason to not “top off” is proffered by the boys of NPR’s hilarious Click ‘n’ Clack show.
They claim that since gas caps are no longer manufactured with ventilation holes that the suction that takes the gas into the engine causes a slight vaccum effect which puts a lot of strain on the engine.
*TIME ELAPSED SINCE I QUIT SMOKING:
Six months, one week, three days, 4 hours, 54 minutes and 54 seconds.
7728 cigarettes not smoked, saving $966.02.
Extra time with Drain Bead: 3 weeks, 5 days, 20 hours, 0 minutes.
The boys at Click and Clack are normally pretty good, but I don’t think they are correct here. And I have caught them messing up a “stumper” before (like the running toilet flooding the house with condensation one, which was absolutely ludicrous)
All of the EEC systems I have seen are designed to allow for pressure equalization in the tank. The two older cars I examined more carefully actually would vent for the tank via a line going to the carbon canister.
And unless we are talking about a mechanical fuel pump (which are rarer and rarer these days) the engine should not care at all unless is has a fuel stavation problem. Wait, let me take that back - even with a mechanical pump, since the stroke of the actuator is fixed, and viscosity of the working fluid does not increase, the engine itself would not see any strain there either.
But fuel starvation can definitely be a problem. And I have also worked on cars that would “starve themselves dry” until the gas cap was opened, which would let in a HUGE blast of air into the tank. And then the pump could get enough suction head so that the car could run again.
Your .23c isn’t much, but there are countless fill-ups everyday. Little bits add up. Vapors from filling stations have been linked to smog. Some states require vapor-recovery type pumps to reduce smog.
I’m not sure why topping-off is a bad idea, but overfilling is certainly bad. Any fuel that spills out either (1) vaporizes into the air (and many of those volatile components are carcinogenic) or (2) soaks into the ground and contaminates soil and groundwater. Since most stations are paved/concrete-covered…most spilled fuel goes into the air.
just had this conversation with my son (16 years old, drivers ed graduate, so naturally expert on everything cars)
He stated that “topping off” was bad for your car. wasn’t sure why.
I couldn’t get how the few more drops one would put in to round up to $15 from $14.93 was going to make any appreciable difference. $0.07 worth of gas at $1.56 per gallon???
Now, although I would ** hate ** to have to go back to him and tell him he was correct, I will if it’s necessary.
So, which is it???
What do you suppose the opposite effect is when you have to stand in line those few extra seconds for the cashier to make change while the bozos behind you in line all left their cars running?
