Never again will I do this...

[bluegrass]

running an empty tank leaves you more susceptible to water vapour forming in the tank.
It can also shorten the life of the fuel pump, as the pump is submerged in the tank. It is lubricated by the gas, so running the pump with little or no gas in the tank exposes it to long term damage.
I had to replace the fuel pump in an older Chrysler minivan, partly because I ran the tank dry all the time. Now I fill up my vehicles when it's down to a quarter tank.

This is incorrect.

Running a modern vehicle to empty does not cause any adverse issues related to water vapor.
https://www.cartalk.com/blogs/dear-car-talk/gas-myths-how-close-empty-it-safe-get

Driving until the 'low fuel' light comes on also does not have any detrimental impact.
Yes, if you "run the tank dry all the time" you might have issues, but that is completely different than simply filling up after the light comes on.
There has ALWAYS been more than 1 gallon of fuel left in the tank when fill up with ~20 miles to empty.

 

[SteveBrickNJ]

Is this the first time you've every put fuel in a vehicle?
Of course you will be OK.
You only added 1.5 quarts (0.39 gallons) of fuel after the pump clicked off.

All gas station pumps are different, pump fuel at different rates, 'click off' at different rates, ect.
The gas station next door could have easily put in that extra 1.5 quarts before the first 'click off'.

You could add an extra 0.39 gallons at every fill-up for the next 100K miles and have no negative impact.

The thing that caused my anxiety and my time on this thread is that my dashboard display did not show the appropriate numbers for "Miles until Empty".
It reflected the same number as when I pulled in before fueling.
Anyway, I'm glad I posted and learned not to add $1.15 even though some say it would be ok...I'm siding with those who advise not to do it again....'cause I won't

 

[bluegrass]

The thing that caused my anxiety...
I'm glad I learned not to add $1.15...
I'm siding with those who advise not to do it again....'cause I won't

I'm sorry for your anxiety, though I'm happy you feel you've "learned" something.

 

[Chas]

This is incorrect.

Running a modern vehicle to empty does not cause any adverse issues related to water vapor.
https://www.cartalk.com/blogs/dear-car-talk/gas-myths-how-close-empty-it-safe-get

Driving until the 'low fuel' light comes on also does not have any detrimental impact.
Yes, if you "run the tank dry all the time" you might have issues, but that is completely different than simply filling up after the light comes on.
There has ALWAYS been more than 1 gallon of fuel left in the tank when fill up with ~20 miles to empty.

OTOH I have read somewhere that “modern” car designs have the fuel pump in the fuel tank purposefully submerged because the fuel pump is cooled by the gas and running the tank empty can cause scoring in the pump which can eventually lead to early fuel pump failure

I don’t have a sense if legit but this is an example of such an article

https://fuelpumpu.com/blog-fuel-system-tips-and-tricks/

 

[yrwei52]

⋯ There has ALWAYS been more than 1 gallon of fuel left in the tank when fill up with ~20 miles to empty.

Actually there’s a lot more fuel than 1 gallon. DBLXX had tested his new 2016 CX-5 and he drove 62 miles to run out of the gas after the Distance to Empty showed 0.

Just remember even if the Distance to Empty shows 0, you may still have about 60 miles to go on CX-5 with 2.5L until you actually running out of the gas! (And its been proven ⋯ )

1st full fill to dry tank drive

Full fill up (to the top of the filler neck) to 62 miles PAST when it initially said "0 miles to empty."

516 miles in total

 

[yrwei52]

OTOH I have read somewhere that “modern” car designs have the fuel pump in the fuel tank purposefully submerged because the fuel pump is cooled by the gas and running the tank empty can cause scoring in the pump which can eventually lead to early fuel pump failure

I don’t have a sense if legit but this is an example of such an article

https://fuelpumpu.com/blog-fuel-system-tips-and-tricks/

Can’t agree with the claims from the article.

The in-tank secondary fuel pump doesn’t have to be submerged in the fuel to get enough cooling. The fuel been pumped will go through the pump and cool down the pump itself if needed. if it’s so important to keep the fuel pump submerged to cool it, what are we going to do on bigger primary fuel pump which is located outside of the fuel tank and may generate more heat?

The theory of sucking more debris into the fuel system with low fuel level is not true either. Not only the pick-up point of the fuel pump has some safe distance from the bottom of the fuel tank, but also the strainer will filter out the damaging debris so that they won’t get into the fuel system, In addition, the fuel filter is the second defense to stop anything armful to get to the fuel injectors.

Ever noticed car manufactures have no longer given any fuel filter replacement interval nowadays. I replaced the fuel filter on my 1998 Honda CR-V at 182K miles for the first time a while ago, there was nothing debris wise I can see in the old fuel filter. Not necessary to replace it just like no replacement schedule suggested by Honda.

 

[SteveBrickNJ]

Can’t agree with the claims from the article.

The in-tank secondary fuel pump doesn’t have to be submerged in the fuel to get enough cooling. The fuel been pumped will go through the pump and cool down the pump itself if needed. if it’s so important to keep the fuel pump submerged to cool it, what are we going to do on bigger primary fuel pump which is located outside of the fuel tank and may generate more heat?

The theory of sucking more debris into the fuel system with low fuel level is not true either. Not only the pick-up point of the fuel pump has some safe distance from the bottom of the fuel tank, but also the strainer will filter out the damaging debris so that they won’t get into the fuel system, In addition, the fuel filter is the second defense to stop anything armful to get to the fuel injectors.

Ever noticed car manufactures have no longer given any fuel filter replacement interval nowadays. I replaced the fuel filter on my 1998 Honda CR-V at 182K miles for the first time a while ago, there was nothing debris wise I can see in the old fuel filter. Not necessary to replace it just like no replacement schedule suggested by Honda.

I keep getting notifications that "so and so" replied to MY thread. Yet you guys are just talking to each other. Get your own thread!

 

[MyFirstMazda]

In the owners manual on page 4-16 it states "We recommend keeping the tank over 1/4 full". They don't explain the reason. My opinion is that they make the pump as cheap as possible and it needs a lot of fuel to make sure it is cooled and lubricated. Has anyone had their fuel pump go bad?

 

[yrwei52]

In the owners manual on page 4-16 it states "We recommend keeping the tank over 1/4 full". They don't explain the reason. My opinion is that they make the pump as cheap as possible and it needs a lot of fuel to make sure it is cooled and lubricated. Has anyone had their fuel pump go bad?

You’re talking about the secondary fuel pump attached to the fuel sending unit here. The failure rate is very minimum and I’ve never seen any reports here even though many of us, including me, waited until the Low Fuel warning light is on to pump the gas. I personally experienced once for secondary fuel pump failure on my 1985 VW Jetta GLI long time ago. But that was due to a batch of defective fuel pumps been introduced into production line and VWoA replaced it for free.

Again, the much more powerful and bigger (more heat) external master fuel pump doesn’t need to be submerged in the fuel tank for cooling, why the smaller and less powerful secondary fuel pump needs it?

In addition, if “keeping the tank over 1/4 full" is so important, then the Mazda would design the Low Fuel warning light lit up at ¼ low.

 

[CarpeDiem]

“Somewhere...”

Should You Keep Your Gas Tank Half Full in Winter?

Cold-climate drivers often wonder, should you keep your gas tank half full in winter? The answer isn't so clear cut.

www.mazdaoflodi.com

Should I really keep my gas tank at least half full?

I've seen a number of sources that state you should keep your car's gas tank at least half full, some of which saying it's only important in winter. Some examples: http://www.osceolagarage.com/why...

mechanics.stackexchange.com

Why You Should Always Keep a 1/4 Tank of Gas in Your Car | YourMechanic Advice

Everyone knows that keeping gas in your vehicle's fuel tank is a must. But you may wonder what the minimum amount of gas is that you should always have in your fuel tank. Some experts claim that you should never let the fuel...

www.yourmechanic.com

 

[clownshoes2]

I’ve been driving for 51 years and at almost every fill up, I try to squeeze in as much gas in the tank as possible. I have never had any problems. I have a 2021 CX-5 and have only filled it about 6 times, but have filled it as full as possible at least 4 of those fill ups without consequences. I have always read that you should NOT top off your tank, but sometimes I wonder if it isn’t to appease the pollution police who don’t want you to spill a drop of gas on the concrete at the pump.

I personally would like to know if any tank toppers like me have ever had any problems associated with the practice.

I've never had a problem. Ever.

 

[CarpeDiem]

My 70-year-old neighbor says he has been smoking 3 packs of cigarettes a day for over 50 years. He doesn’t have lung cancer....

 

[Buzzman12]

My 70-year-old neighbor says he has been smoking 3 packs of cigarettes a day for over 50 years. He doesn’t have lung cancer....

I bet he smells good too.

 

[Silly Wabbit]

My 70-year-old neighbor says he has been smoking 3 packs of cigarettes a day for over 50 years. He doesn’t have lung cancer....

He could have driven a Ferrari if he didn't smoke his money away

 

[ACSCX5]

Here are my personal two reasons for not allowing my tank to remain low for very long:

If the tank is 1/4 full of gasoline, then it is 3/4 full of air, which contains moisture. With day/night temperature changes, that moisture can condense resulting in water in the fuel. If I know that I am not going to drive my car for a few days, I like to make sure that my tank is full of gas to minimize the air, therefore minimizing moisture.

Also, in the winter months, having the extra weight of gasoline in the tank helps with traction in snow.

These are great reasons here in Michigan, but may not be as important in Arizona.