Gas tips correct or legit?

I recently received an email with the following tips… maybe everyone has but seems interesting concepts (because of the reasons listed) ((somehow I fall for reasons)) So, how real are these tips? Especially #3… I always wait until I’m practically pushing my car.

1. Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the gasoline, when it gets warmer gasoline expands, so buying in the afternoon or in the evening…your gallon is not exactly a gallon. In the petroleum business, the specific gravity and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products plays an important role A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps

2. When you’re filling up do not squeeze the trigger of the nozzle to a fast mode. If you look you will see that the trigger has three (3) stages: low, middle, and high. In slow mode you should be pumping on low speed, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you’re getting less worth for your money.

3. One of the most important tips is to fill up when your gas tank is HALF FULL. The reason for this is, the more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation.

4. If there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up–most likely the gasoline is being stirred up as the gas is being delivered, and you might pick up some of the dirt that normally settles on the bottom.

  1. Doesn’t make much difference, the tank is buried underground and doesn’t change much, if at all, in temperature during one day. Winter vs. summer, sure, but that’s not what we’re talking about here.
  2. I can’t imagine this makes much difference, but you can try it and see.
  3. Tanks are now sealed, with vapor returned to the engine. No impact.
  4. Could be true, but the pumps have filters.

All these points are true in some ways. Item (4) was very true years ago when pumps did not have proper filters. It’s much less relevant now.

If you do all these things you may save some money over a year but not nearly as mcuh as, say buying coffee at MacDonald’s rather than Starbucks, and eating small hamburgers in stead of whoppers.

I spent $745 dollars on gas last year for my one car (we don’t drive as much anymore), and spent over $1200 eating out! You get the point.

The biggest gas saver is being easy on the gas pedal, and driving defensively, so you never have to jump on the brakes.

In summary, I’m not againt the 4 points you list, but there are many easier ways to save gas in a meaningful way!

You could do every one of the four and not save enough to notice. Keeping your tires correctly inflated would make a MUCH bigger difference than any of this stuff.

IMHO, the fixation on vapors is ridiculous.

Who makes this stuff up, anyway?

Urban legend. Went around the internet a long time ago. Debunked on

It’s the ‘magic diet pill’ syndrome - ‘I want something simple to solve my problems’, instead of changing how I drive, or the vehicle I drive. Wish it was that easy.

Tip: Most emails are unreliable at best. They take a little truth and stretch it to an entire story. Don’t put much belief into emails because they are just electronic National Enquirers for the most part.

If you saw the people who make this stuff up…

If you now get 25 mpg, you may improve that following those rules to 25.00001 mpg. Good Luck.

  • 1 & 2 are correct, but immaterial.
  • 3 is meaningless.
  • 4 is correct, but is very seldom a problem. Filters have eliminated the problem in the late 1960’s or there about.

Most of these came from the old days of fueling, but not so any more.

1 - true in theory BUT…
the reason the tanks are in the ground in the first place is for temperature stability. ( Think how deep your plumbing is buried below ground, below the frost line, for the same reason. ) As well as efficient use of land acreage…oh yah,and to hide any leaks until twenty years after the fact.
It takes a gawd awful long time for those tanks to increase in temp. THAT’s why they’re in the ground. If you see an above ground holding tank ( Petro truck stop, Grants NM ) then maybe.

2 - possible BUT…these days pump technology has them “accurate at all deliveries and pressure” to be certified. Only the shady sheister stations would have otherwise.
Next time you fill your can for your lawn mower/weed eater/chain saw take TWO jugs to your regular station to test their individual accuracy.

3 - In my Cessna gravity fed non-pressurised system, it is a very real stuation of water condensation in the fuel tanks. So real that they have a drain valve ( water is heavier ) for removing any water every preflight procedure. A full tank has no space for condensate to form ergo less problems.
But not so in automotive systems…these days.

4 - Alas, the advances in required technology for filling stations ( filters ) would have one being leery of the shiesters but not the name brand and top notch places.