Okay here is a stupid question

[Horse with no Name]

What "exactly" is topping off?

[knowbody0]

1. filling your gas tank

[Captain Hilts]

3. Filling your gas tank that extra bit after it has racheted off. nt

[lectrobyte]

2. filling up your tank, but implying only needing a few gallons. nt

[El Supremo]

4. Do you mean "overtopping"?

In that case it means the lake rose over the lowest levee repairs. I don't blame the Corps of Engineers.

[bonito]

5. The act of beheading? n/t

[nonconformist]

6. When you're filling your gas tank, the nozzle auto clicks off

when it's full. However, if you pull the nozzle out just a tad, you can fill it even further a bit... aka as "topping off".

[Robertwf]

7. Not Just Filling It

It's putting those last teaspoons in, even though you already have 7/8 tank. Ya got your folks that like to have the tank absolutely full-full and then ya got your folks that run it down to the fumes before they put another 50 cents' worth in.

[jobycom]

8. What nature did to me

[titoresque]

9. Yeah and why is it so bad?

I dont get it! It's ok to fill your huge SUV....but DO NOT ADD THOSE TWO EXTRA TSP's!!! Huh? Someone please explain the reasoning here?

:shrug:

[VolcanoJen]

12. I think they discourage topping-off at the gas stations because...

... gas tends to spill out when you top-off and they have to clean it up. It's an environmental hazard, and let me tell you, those crews that they bring in to clean up the concrete at gas stations make very good money.

I'm a serial top-offer, though. I take care not to spill, but I top off.

[Oeditpus Rex]

13. One, it's too easy to spill

When you top off, you're liable to overfill and have gas run out the filler neck. Besides being a waste and a fire hazard, it's bad for your car's finish.

Two, it can be dangerous to top off certain types of tanks. Fuel-filler caps come in "vented" and "non-vented" varieties. (Your owner's manual should tell you which you have.) If you fill a non-vented tank to the brim, the air pressure from the cap can conceivably create an explosive situation.

[titoresque]

14. Thanks Rex, thanks Jen

I thought it had something to do with using extra gas? I dont know........

Thanks, I never top off mainly because I'm always in such a hurry to get in and get out of there. I've run out of gas so many times in my life for the simple fact that I hate to stop at the gas station....doh! I've gotten better especially now that I have fuel injection.....can't let it run too low.

Thanks for the explanation.....I have more reason now NOT to top off

:toast:

[Igel]

10. There are two definitions.

If your tank's near empty, topping off means to put in that last extra bit.

If your tank's near full, it means filling in to buy a pint of gas while the buying is possible. In this sense, I usually put about 3/4 tank as the cut-off. Below that, I'm just filling up (seldom done, except before a long trip).

[Gold Metal Flake]

11. Allow a gearhead to weigh in.

Topping off is a term applied to the act of adding gas when you are only down less than 1/2 a tank. Instead of waiting until your tank is near empty to fill up, you "top it off" when you are about 3/4 or so. Like, just keeping it full as much as possible, so you are always prepared for an extended period of driving.

Topping off is only a problem as far as congestion at the pump is concerned. You don't use any more gas than you would be otherwise, but you are blocking a pump frequently during periods of high demand.

[osaMABUSh]

I never top off - i wait till i'm on fumes before refilling

of course, driving a Honda Civic means I can go about 400 miles before I get my 10 gals.

I love driving by gas stations - not needing to fill up.

[lectrobyte]

17. Yeah, that's what I've always considered the definition of "topping off"

I didn't know they had a word for continuing to pump gas after the automatic cut off kicked in. I always called that "rounding up to the next 25 cents" in my head since I don't like to carry much change and want it to come out even.

[daleo]

15. In normal situations, topping off could result in more smog

The volatile parts (i.e. light and quick to evaporate) of gasoline are important contributors to smog, which is why gas tanks and nozzles have those shut-off features now. When many people try to "top off" they add that extra amounts of that volatile hydrocarbon component to the atmosphere, more than they would otherwise, which result in additional photo-chemical smog.

Other than that, I am not sure what the problem is, other than just causing longer lineups at gas pumps than necessary. If everyone tops up, they might fill up twice to get twenty of gallons of gas, rather than once, resulting in longer lineups.

[Ilsa]

16. We have stickers on the pumps at our local EXXON

stations explaining that topping off does add more hydrocarbons to the air resulting in more pollution and smog and ozone depletion. The stickers say "Stop at the first click" or something like that.

[daleo]

18. Yes, the hydrocarbons are vital to the production of smog

I think they are catalysts (so they add more to the reaction than just their physical presence might indicate). Anyway, that is a vague recollection of my high school chemistry.

[Gold Metal Flake]

19. Spillage is the concern.

When you continue to fill after the automatic shut-off, you risk fuel being "burped" out of the filler neck. This fuel splashed and drips or pours out onto the car body or ground and evaporates, contributing to ground-level polution. Multiply by thousands of times a day everywhere and you can see how it's a concern.

Some cars burp worse than others. My 1968 Mercury Cougar (similar to the Mustang) is prone to doing it.

I have a problem resisting the urge to get in all that I can. But, with age comes moderation.

[Jamastiene]

20. There is no such thing as a stupid question. Only stupid answers.

Filling up the gas tank to the top. Or refilling your drink to the top. :toast: