Gas station myth or fact: What you need to know when you refuel

On any given day, some 40 million Americans stop at gas stations to fill their tanks. For many, it's a weekly routine, one they don't spend much time analyzing, but are there things you think you know about your fill-up that just aren't true?

Andrea Kaufman considers herself a fairly conscientious auto owner, but the St. Louis Park, Minnesota resident admits she doesn't know the finer details of pumping protocol. "I've heard plenty of gas station tips and tricks, but I'm not always sure which ones I should believe."

Let's set the record straight as energy experts dispel three common gas station myths.

Myth #1: It's best to buy gas early in the day.

The theory is that gasoline is denser at cooler temperatures, so you'll get more fuel per gallon early in the morning. While the basic science is correct, the experts at Consumer Reports point out two practical reasons why this is a myth.

First, most gas stations store fuel in double-walled underground tanks that keep gas at steady temperatures. Second, even if there were variations, the volume difference between gasoline at 75 versus 60 degrees Fahrenheit is just 1 percent - not enough to be noticeable at the pump.

Myth #2: It's dangerous to use a cell phone near gas pumps.

According to the Federal Communications Commission, there is no documented incident of a wireless phone causing a gas station fire or explosion.

It's true that many fuel companies post stickers on pumps warning motorists to turn off phones while refueling as cell phones could be a distraction. But the Petroleum Equipment Institute (PEI) reports the most likely cause of fire at the pumps is static electricity created by drivers sliding in and out of vehicles. For safe refueling, PEI recommends you turn off the car engine, refrain from smoking and stay outside the vehicle.

Myth #3: All brands of gas are the same.

Like more than two-thirds of Americans, Kaufman buys gas primarily based on price and convenience. "I don't know if there is a difference between brands," she says. While all gasoline sold in the U.S. must meet federal requirements for performance, not all gas is the same.

The auto industry has a certification system for fuel. Top Tier certified gasoline includes additional detergents and fuel additives that remove engine deposits that can hurt fuel economy.

"Today's more fuel-efficient engines need higher-quality fuel for peak performance," says Akhtar Hussain, refined fuels expert at CHS, which markets Cenex brand fuels at more than 1,450 gas stations in 19 states. "Cenex TOP TIER Detergent Gasoline provides 2.5 times the cleaning power of conventional gasoline and removes deposits for better fuel economy and reduced emissions."

Our Top Tier certified gasoline keeps newer high-precision engines clean and helps older engines perform better, he adds. "It helps clean your engine every time you fill your tank." Cenex TOP TIER Detergent Gasoline is available at every Cenex location. To find one near you, visit cenex.com/locations.

So much for those tank-filling myths. Now it's time to fuel up and enjoy the drive.