Topping off the tank

does anyone have a stat aboput how much gas is spilled (topping off the tank, general sloppiness, etc) at US service stations each year?



I don’t know how they could really track something like this but if such a thing exist i’d like to see it too.

I don’t know what the stats are , but I’m guilty of doing it. On my Bronco I can usually get another 2 gallons in after the pump clicks off. In my Mustang, I can only get another .4 or .5 gallons in. The TR6 is intresting because it’s filler is vertical, so when then pump clicks off it’s full.

On my '89 Accord the fuel literally just starts to overflow out of the tank as the pump shuts off. Sometimes it splashes out or stops right there.

On some vehicles “topping off” can cause fuel to get down the line and saturate the charcoal bed in the charcoal canister, interfering with the ability of the tank to breath in as the pump draws gas out. This can cause operating problems and even premature pump failure.

i’m pleased that it’s been working for you, but I recommend against the practice.

Agree; modern cars are to be filled until the first click. Where my wife tanks, the kids try to get more in (nearest $$) so they don’t have to make change. I’ve told her to have them stop at the first click, or pump her wn gas.

I’ve even seen a kid at a gas bar, after topping off a customer’s tank, spill the rest on the ground just to to the nearest dollar.

I guess the fact that there is a possibility you may get a “code” is secondary to the fact you already have a problem, wether it be this on or something else. I drive a 2006 Honda Civic and the manuel advises against the practice because there is that very possibility (problem and “code”). For years (but not recently) I would routinely top off to the nearest dollar if possible. Now, because of the various advantages available, I always use a credit card and rounding off just doesn’t seem to mean anything at all anymore.

“manuel advises against the practice”

So do Juan, Miguel, and Jose!


Got me!!
Good one :slight_smile:

I have always topped off the tank because I want to calculate my mileage as accurately as possible. I had terrible idiot light problems with my '02 Focus and was told topping off could have contributed to the problems. I spent $600 plus to finally get both the check engine and the gas cap warnings removed. I am really struggling not to top off my new Matrix, but my fanatic cumpulsion to keep extremely accirate mileage has won the last two times I filled the tank. If I knew that the automatic pump shut off at various pumps always left the car with the same number of gallons I could make myself stop. Before I used credit cards for every possible purchase (I get nice perks from my AAA Visa) I still didn’t care if I reached a full dollar amount. With credit, it doesn’t matter. My father was a truck driver and always preached that if we didn’t track gas mileage we couldn’t accurately evaluate performance. It really kills me not to top off.

Those nice round numbers cost you a round $600 plus, didn’t they? Try again?

I wasn’t after round numbers–I wanted a completely full tank each time. When that $600 was followed by another $200 in about six weeks, I decided to trade the car. Now I am struggling not to do it again with the new car, but I am compulsively interested in knowing my mileage. I also have another reason for squeezing in every drop possible–the gas will certainly cost more the next time I fill up and I want to buy as muck as possible at today’s price :frowning: I was filling my tank at $3.499 today while the attendant was changing the prices to go up a penny. When I was a teenager and there was a gas war on the Berlin Turnpike in CT, it was 18 cents a gallon. My mother used to give me $2.00 to put in the tank and it would last several days. When I turned 21 I bought my first pack of Salems for 28 cents! I have long given up smoking but I can’t stop using my car–I live way out in the country. Damn!

do not top the tank,as the posters said BIG PROBLEMS WILL OCCUR.and big cash.

There are a few make/models that apparently develop problems if overfilled. Others are completely immune to overfilling. Fill these to overflowing if you like; they can happily take it. If you have already topped off a car several times and experienced no problems then you can make this your fulltime habit for that car. Just try not to spill anything.

ComputerDyslexic, your habits resemble my own. So let me remind you it is not necessary to top up to obtain mathematical accuracy. Your calculations per tankful are rather meaningless anyway. Well, maybe they are a crude guideline for city vs. highway mpg. But it’s generally only the longtime results are meaningful. And these results do not require filling up evenly each time.

I see you have a problem with the concept of penny proud and pound foolish. Oh, well, it’s your pounds.

Rounding off to the nearest dollar is no longer a big deal with todays prices since that means, what, adding an extra 1/2 pint? ;o))

I live in a state where we can not pump our own gas; the attendant does it. Well, everytime I would ask them to fill my tank they always topped it off. To prevent this I now ask for only $30 or $40 in gas, so I don’t have to worry about them topping it off and wrecking my fuel filter.

You can calculate the exact mileage with a $10 pocket calculator; I keep one in the glove box. I measure the mileage every 5 tanks or so to get an idea what is going on, if anything.

$600? Sounds like the canister. Plus labor.

You have an expensive compulsion there.

That is true, but you also can’t calculate your gas mileage unless you fill the tank.

IMHO, regular checking of a vehicle’s gas mileage is a good basic diagnostic tool that can give you an indication that something is amiss, and that is why I do it. (My driving patterns are so routine that my gas mileage does not vary beyond ~ 1/2 mpg to 1mpg, so if it was to drop off more than 1 mpg, I would start looking at possible problems with the engine or perhaps a dragging brake caliper)

Anyway–I also live in a state where you are not allowed to pump your own gas–NJ. What I do is to get out of the car when I know that the tank is almost full, and before the attendant has a chance to start clicking the pump handle to force more gas into the tank, I tell him “That’s good–No More”, or in some cases I will say “Bastante” if the attendant is Hispanic.

This way, my tank is filled, but not over-filled, and I can calculate my gas mileage. Why don’t you give my method a try?

ADDENDUM–Litahni–It’s not the fuel filter that you have to worry about, but rather, the carbon canister. The difference in price between these two different components is frequently ~$300.00–or more!