When to fill up the tank

[AMX]

I apologize if this has already been covered in another thread. However, my question is: Is it better to fill up the gas tank when it's near empty, or when it's half empty? There is less weight, therefore some better mileage can be gained when the tank is near empty, however I have also read that with a small amount of gas in the tank, a lot can evaporate. What are your opinions on this?

[jadziasman]

Always better to have less fuel in the tank for less weight.

If you always go to the same gas station and same gas pump the same time of day and drive the same route at the same speed you will eventually be able to find out the absolute maximum number of miles you can drive before you must get gas.

Works pretty good most of the time. But with E10, you might get an unpleasant surprise once in a while. Then you're EOC for real LOL!!!!!!

[theholycow]

The downside of running on empty all the time is excess heat in your fuel pump resulting in premature failure. Modern in-tank fuel pumps depend on being totally submerged to dissipate heat.

[cems70]

Originally Posted by theholycow

The downside of running on empty all the time is excess heat in your fuel pump resulting in premature failure. Modern in-tank fuel pumps depend on being totally submerged to dissipate heat.

Being the poster child for running my tank almost completely empty before filling up, I have to disagree. I bought a Civic VX brand new in 1995, always ran it close to empty before refilling (i.e. the pump usually stopped at 9.5 - 9.8 gallons for the 10 gallon tank), and I never had any problems with the fuel pump in the 225,000 miles I drove the car. I also used to overfill it with 3 - 5 gallons extra, after the pump stopped. I could trickle it in slowly. Believe it or not, I never actually ran out of gas...came close 2 times, but always made it to the gas station.

[1993CivicVX]

Originally Posted by cems70

Being the poster child for running my tank almost completely empty before filling up, I have to disagree. I bought a Civic VX brand new in 1995, always ran it close to empty before refilling (i.e. the pump usually stopped at 9.5 - 9.8 gallons for the 10 gallon tank), and I never had any problems with the fuel pump in the 225,000 miles I drove the car. I also used to overfill it with 3 - 5 gallons extra, after the pump stopped. I could trickle it in slowly. Believe it or not, I never actually ran out of gas...came close 2 times, but always made it to the gas station.

At times, I've put 11 gallons into my gas tank. How many gallons have you put it in one fill up?

[theholycow]

I can counter your data point with a fuel pump that died at 120,000 miles. Perhaps a 1995 VX fuel pump isn't very sensitive to heat...

[VetteOwner]

Originally Posted by theholycow

The downside of running on empty all the time is excess heat in your fuel pump resulting in premature failure. Modern in-tank fuel pumps depend on being totally submerged to dissipate heat.

yup, ive heard of this happening in the s-series GM trucks and blazers

whoppign $300 to replace soo id rather not risk it

[101mpg]

You're also best off to fill up in the morning. I see about a 3% difference - so much so that it's been YEARS since I did a regular fill in the daylight hours. Usually fill up between 6 and 8 am. Many years in the desert taught me this one.

[civic94]

summer's coming and it gets to the 80's and 90's here, should i fill up with 1/4 a tank with my 94 civic?

[AMX]

Originally Posted by 101mpg

You're also best off to fill up in the morning. I see about a 3% difference - so much so that it's been YEARS since I did a regular fill in the daylight hours. Usually fill up between 6 and 8 am. Many years in the desert taught me this one.

Here in Canada the pumps are temperature compensated, so there wouldn't be much, if any, difference.