I'm not sure if this has been discussed or not before, and YES I did do a search which produced lots of garbage! I was wondering if anyone tops off their fuel tank? That is to say when you fill up and your automatic shut off activates at $18 but you put $20 on so you pump on that extra $2? The real issue here is whether or not that is wasted gas, and I ask because I have heard varying opinions. Some say that as long as it’s not so full that gas actually overflowing your fine and others say that once you hit automatic shut off that’s all the gas your tank will hold and it’s lost to spillage. My only problem with the otherwise plausible theory 2 is that even if you fill up past the automatic cut off, how would the gas spill once you have sealed the tank? As you can see I’m quite conflicted here and many of the participants on this forum are more knowledgeable than I so any help would be great. ALSO if someone wants to be a real smart ___ and say "read the manual" or something along those lines, F*CK YOU, I’ve done that; I’m looking for advice not your cynical remarks.

 

I too have heard 2 stories on that issue. I have heard that it's ok to top off but then again I've heard, Not too. The reason most manufacturers put in that feature is for the reason of not topping off. Meaning the auto cut off. You need extra room in your gas tank to allow the gasoline to expand. If you top off your tank, the extra gas may evaporate into your vehicle’s vapor collection system. That system may become fouled and will not work properly causing your vehicle to run poorly and have high gas emissions. They do this in order to fill the tank with gas but leave just enough space for air to fill the gap. That way as you burn more gas you don't run the chances of something happening as far as over combustion or not using the gas efficiently. It has something to do with the way the pocket of air creates a vacuum that helps the gas flow properly and get used more efficiently. In my opinion all the manufacturers would'nt have built in this feature if it wasnt for a purpose. Either way if your only getting a extra 2 bucs while topping off, then to be on the safe side meet the process in the middle. Top it off 1 buc and u should be ok. I hope this helps.

 

I believe the owner's manual says not to fill above the automatic shut-off point. The tC has a charcoal filter assembly that the gases from the fuel tank vent to (I'm not sure if they go back to the tank or to the engine somehow.) If you overfill the tank you run the risk of contaminating the charcoal filter assembly.

 

I top off my current car JUST A LITTLE because if I don't, it will only take like 8.5 gallons and when i turn it on, the needle won't even be touching the start of the full marker. If I do top it off, it will only be one time over where it shuts off the first time - no super duper anything - just enough to get the car to think the tank is actually full. I'd never to it to the tC, especially because I've heard about that charcoal filter, if not for the increased environmental risk when you end up spilling gas (any gas) on the ground. Oh... and when you give them 20, you can get change, you know? I'm a cheap bastard, but I've got no problem getting $.50 back and worrying about what to do with it later.

Oh... I also just use a credit card for gas. I get 5% cash back when I buy gas with it and you never have to waste time going inside and you don't have to top off to get rid of that last buck or two.

 

yes if you overfill it (go beyond the auto shut off) you will saturate the evaporative emissions controls.. no matter if you wanted to not get $0.50 back in change.. it will ruin it.. so hey i guess it's your money.. since the dealer will be able to tell that you overfilled the tank over and over again and ruined the emissions system.. but hey it's your car..

 

A extra $2 for me around where I live is a extra gallon+. I normaly just top of to the next dollar. Most of the time I get lucky so its only about another $.30 worth of gas so not to much harm.

 

i actually wrote a good post about this on my friends forum

here is the link

http://ysian.com/phpBB2/viewtopic.php?t=19

 

I don't top anything off since I live in NJ

But I prefer that they fill my tank as much as possible, because it means more time before I have to go back to the gas station again.

 

I Live in Southen Oregon, When I fill up my box in oregon, it will always go up to the "full" mark on the dash. Last weekend I took the box to Southern California (and got 40 MPG BTW!!), and every gas station I went to in California has a special nossle that will not let you "top it off" . ARGGHHH! every were I went in California (only Cheveron stations) I could not fill my box all the way!!!! I would only go 1/8" from the full line.

So the bottom line is dtemple, your not crazy!! Oregon is one of the only states were your not allowed to legally pump your own gas-thus we dont have those lame filler nossels....

And if you lucky enough to find a gas station that has a pump that will allow you to top it off- the gas is fully going in your tank. All gas tanks are sealed- the only entry
( and exit ) is the filler neck.....