Everywhere I have read, everything I can find, says I have a 13 somethim gallon tank. My cars manual, Mazda's website, other sources (Edmund's, car comparison websites etc.) They all say 13.2 gallons.

How is that I only fit an average of 9 to 9.5 gallons? Today I ran the car as empty as I felt comfortable doing. In other words, I drove until there were no notches on the fuel gauge, and the range said 1 mile. The gal working squeezed in 9.8 gallons, only after I told her to top it off from 9.6, and check to make sure it wasn't clicking early.

My fuel gauge reads full after fill up, so it's clearly filling all the way. If it matters, I average about 23 mpg town, and 34 hwy. 27-29 mixed.

Any ideas?

 

Here is a photo.

 

Anyone?

 

Never run around with the fuel light on. The fuel pump relies on sufficient fuel surrounding it to keep itself cool. Low fuel level will cause the pump to overheat & fail prematurely ( over time ).

Also its most unlikely you could suck up all the fuel in the tank thru the pump.

And to prevent stupid people ( not calling you stupid ) from running out of gas after the Distance to Empty drops to zero, the calculations cover this situation.

 

3.6 gallons just seems excessive. I'd even understand 2 gallons more than 3.6 gallons. I don't run around with my fuel light on, I was just running it "empty" once to see the capacity. But if it has 3.6 gallons left I'm sure it won't harm it to run it to that point. Like you said, they do it to prevent harm. So it shouldn't matter now with this car to let it hit E, because that few gallons is still there keeping the pump submerged.

 

Not saying it is but it could be an issue with the fuel level sending unit.

 

It's possible. But the fact that the tank reads full correctly makes me think otherwise. Does anybody else have a Mazda3 that can chime in?

 

It seems to be common after doing some more research. The reasons range from reserve fuel, vapor headroom, pump submersion, and leeway for the readouts. Mazda just took it an extra step this time. Or the tank is designed in a such a way that the profile of the bottom won't allow for adequate submersion of the pump without a few gallons in it. Either way, it doesn't seem to matter much.