Keeping Gas Tanks Full in Hot Weather to Prevent Fuel Pump Failure

L

Lonnie

Active member
Because fuel pumps in modern cars are located INSIDE the fuel tank and are electric motor-driven, I was told that gasoline acts as the coolant for them in Hot Weather and it is best to keep your gas tank filled and never run it under a quarter tank in Hot weather, as this can expose the fuel pump and cause it to overheat or even fail.
Any Autopian have this experience or heard of this?...just Captain Obvious curious 🧐.
 
I`ve heard it was a good practice regardless of the weather for the reason you already mentioned. Even in the cold, that pump would be working hard and you don`t need it running without any cooling.

What does seem up for debate is the "safe" level of fuel in the tank. My option: it varies depending on the car. From some math I did while filling up our Toyota Highlander, I figured the tank would have at least 3 gallons left when the needle showed empty. The light would come on with something ridiculous like 5 gallons left. However, an E46 BMW I owned many years ago was calculated to be almost bone dry if the needle ever rested on "E". Not only will the calibration of the gauge have an effect, but the shape of the tank may too. If the pump sits in a low spot of the tank, you`d have a margin of error a flat bottom tank would not.

The other problem I`ve heard about running the tank really low is the risk of any sediments in the tank getting ingested into the pump and possibly heading upstream to the engine. Hopefully the fuel filter would catch them, but there is still a higher chance when the gunk has a better chance of setteling around the pump vs sloshing around in a full tank.
 
The late John Lingenfelter was a big supporter of this, keep tank full to keep the pump cool = longer pump life. Now he was a big racer and engine builder, so racing aspect changes things. But for cars on the road, he talked of this. Ever since I heard him say that, I listened and have always kept the tank as full as I can. I have always looked at the 1/2 tank mark as empty, kind of always topped up. And I know at the end of the day, so to speak, you use the same amount of fuel, but adding $20 of fuel here and there doesn`t seem to sting as much
as adding $100 at once. Mentally that is, lol;)

And before hearing the above in winters it was always taught up here to keep the tank full. Good practise and also add some weight. I have kept the tank full all seasons.
 
Silly Rabbit said:
The late John Lingenfelter was a big supporter of this, keep tank full to keep the pump cool = longer pump life. Now he was a big racer and engine builder, so racing aspect changes things. But for cars on the road, he talked of this.
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Heat in that environment is a big problem, but so is fuel starvation in hard cornering or acceleration. If you tank is low enough on a twisty mountain road, the same thing can happen too just driving normally.
 
Our 2015 Ford Taurus has a push button starter, so you need to step on the brake BEFORE pushing the "start" button and when you do, the fuel pump kicks in first.
I know that because when I push the brake pedal, I can hear it if I delay using the start button.
Sometimes I do this on Sub-Zero temp days, just to prime the fuel system. Kind of like the old days of the carburetor when you press the gas petal and let up to prime the jets and /or set the choke.
 
I wait until my gas light comes on to get fuel. Life is too short to worry about a stupid fuel pump. Other than Accumulator is there anyone here that keeps cars for over a 100k miles?
 
Dan said:
I wait until my gas light comes on to get fuel. Life is too short to worry about a stupid fuel pump. Other than Accumulator is there anyone here that keeps cars for over a 100k miles?
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I`d guess anyone who has a Honda, Acura, or Toyota can easily go 100k miles and then a few more of those, so those guys... :)
Dan F
 
Stokdgs said:
I`d guess anyone who has a Honda, Acura, or Toyota can easily go 100k miles and then a few more of those, so those guys... :)
Dan F
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Not how long they last, how long present company keeps them. Many here are serial car switchers. I`m on my longest yet with my Corvette being 13 years old!
 
Dan said:
I wait until my gas light comes on to get fuel. Life is too short to worry about a stupid fuel pump. Other than Accumulator is there anyone here that keeps cars for over a 100k miles?
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I own 7 cars. My 2004 VW Touareg has 250,000 miles and my 2005 Mini Cooper S has 120,000 miles. I have never replaced the fuel pumps on them. I was taught to always keep the fuel tanks full. and rarely let them drop below 1/2 tank.
 
Dan said:
Other than Accumulator is there anyone here that keeps cars for over a 100k miles?
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I sure do. I can only think of a couple cars I`ve owned that didn`t have over 100K before we swapped them out.

My wife`s last car, the Toyota Highlander I mentioned was put to pasture with 340K on it. Her car before that had 210K on it. I traded in my last car with only 70-ish to avoid nightmare repare costs. My very first car I had to trade in at around 95K due to GM malise-era build quality. Both my daughters (on their own now) are running cars with near or over 100K mileage too.

Overall, we as a family don`t even blink when our cars roll over 100K.
 
Since we are diverging a little from the topic of fuel pump replacement and getting into high-mileage vehicle driver-ownership, I can somewhat make the blanket statement that with new(er) vehicles, you are making car loan payments Or with high-mileage older vehicles you are paying for repairs. It can be (and is) expensive either way and I am sure many of you with older vehicles come to that crossroad of do I pay for the repair or get some different vehicle.
Yes, I am guilty of sticking a lot of money in my own 2006 Ford Freestyle; more than it`s Blue Book wholesale worth , BUT I know the vehicle and what it is like and the purpose it serves.
Last year I put about 3,000 miles on it and most of that was going back-and-forth to my church ( yes, one of "those" vehicles and its driver!)
 
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