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Question about fuel endurance

Hi everyone,

If the owners manual in my car says that my fuel tank holds 17 gallons, is it reasonable to assume that all 17 gallons are usable?

Last night on my way home I “dipped into the reserves” (Fuel gauge BDC, warning light on) and still only pumped gallons.

So if my car gets 28 MPG, then theoretically would I have made it another say, 56 miles? Thanks


I Have Only Run Out Twice. Like You I Always Tried To Blame Somebody Or Something Other Than Myself."

This question comes up many times. The fuel tank capacity stated in the ownwer’s manual is exactly that; the amount of gas the tank will hold. Fuel gages and warning systems are designed to keep you out of trouble, so the indicate empty or flash a light quite a while before you run out of gas.

Last year I drove my Toyota for 30 miles with the fuel light on since the gas station on that highway had closed down and I had to get to the next one.

Tom and Ray answered a question on this topic a while back, and their response was something like; “if the light goes on, fill the tankk to the first click, count the gallons and compare that figure with the one in the owner’s manual. The difference is what you have left when the light goes on”.

Hope that naswers you question.

Hypothetically, yes. But it really depends on what mileage you get that particular day. When I get low enough to turn the light on, I stop thinking about where the cheapest gas is and find a station. Unless I’m at work, I’m not close enough to the cheap gas to get it.

Perhaps, but one thing I can tell you for certain is that if you make a habit of “dipping into the reserves” you risk running dry and that is not condusive to long fuel pump life. There is a risk there.

I can also tell you for certain that if you fill the tank when it nears the 1/4 mark it won’t cost you any more in the aggregate than if you keep running it down to the warning light level.

Personally, I keep it above 1/2 in the winter. I commute, and I don’t want to be stuck with the low fuel warning light on in the middle of a snowstorm on a highway stopped dead for an hour due to a pileup. It happens often on the Everett Turnpike.

Most reserves for the low fuel light about 2 gallons worth of fuel. If you happened to be getting 28mpg then yes another 56 miles.

You’re asking for trouble.

You should NEVER let the fuel gauge go below 1/4 full. The fuel pump is inside the gas tank, and is cooled by the gasoline in the tank. If you let the tank get close to empty you are removing the coolant from the fuel pump, which is expensive to replace.

Hoping to scrape the last few miles from every tank of gas is false economy. You will pay more in the long run for repairs than you will ever save in up-front fuel costs.

Rethink your strategy.

Actually, often times the answer is no. The fuel tank capacity that’s listed sometimes is the gross capacity of the tank itself. The fuel pump and pump sender take up some space in the tank and, also, depending on how the tank is shaped the last gallon or so usually aren’t usable because the level will be so low that the fuel sloshes away from the pump pickup, which will cause a fuel injected car to sputter and die.

I was driving my Bronco a few years ago. The gauge was slightly past the red slash. I was about 5 miles from my exit and there’s a gas station right off my exit. So I decided to chance it.

About 4 miles from the exit, the engine started sputtering. I weaved from side to side to get the last drop of gasoline to the pickup. It stopped stuttering for a short time. Luckily there was another exit about an 1/8 of a mile down the highway. I make a quick exit, but I have to stop at the end of the exit ramp. At the intersection I spy a gas station about a 1/4 mile down the road. I make the right onto the surface street and try to accelerate. The Bronco is sputtering ferociously, it coughs and wheezes its way up to 35 MPH. And then about 100 feet from the gas station it finally stops sputtering and dies. I manage to coast into the gas station and stop right next to the pump, amid a thumbs up and a high five from the people who were there pumping their gas and saw me coming down the road with rough/non running engine.

An interesting side note. The tank in the Bronco is 32 gallons , but I was able to get slightly over 33 gallons in it that day.

lol, great story.

FoDaddy, Belated Thumbs Up From Me, Too. That’s A Great Bucking Bronco Story!

I could picture the whole thing. I’ll bet you just hopped out and filled up, right in front of the spectators, just like you do this stunt everyday. But I’ll also bet that you watched the gauge just a little closer for a while. That’s funny.

It is also worth it to bear in mind that the proper operation of that warning light normally depends on an accurate fuel level gauge. I happen to have 2 vehicles with fuel gauges that are a bit wacky - so, e.g., I can’t use the Tom & Ray method to decide how soon or late my warning light turns on. Like others here have mentioned - I just don’t play with this kind of thing, and don’t let the tank run down from multiple reasons.