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Author	Topic: Is it better to fill up a gas tank when it reaches half or almost empty?	Topic is locked Back to Topics

PwrStroke Rookie Author Phoenix Posts:12 Points:13,215 Joined:Aug 2005	Message Posted: Aug 24, 2007 3:12:12 PM Ignore PwrStroke Report Abuse First answer by Ask Hutch Ask Hutch. Last edit by Paul2006. Answer The last answer is correct, with an electric in-tank pump never let it go below 1/4 tank. Answer It used to be advised not to let the fuel get too low in the tank. This was because dirt could lay in the bottom of the fuel tank, this dirt could then be picked up and block fuel lines and jets. Fuel these days is so well filtered that this is no longer a problem so it makes no difference when you decide to add more fuel. Answer It depends on what you are trying to accomplish: 1- In the winter it is better to fill the tank ASAP to prevent moisture from potentially freezing the gas line and from running out of gas due to unexpected traffic or weather related issues. (Not an issue in PHX Az) 2- If you are trying to save on the extra weight of gas then fill close to empty. 3- If you are mixing lo and hi octane gas then do it at 1/2 tank. 4- In the summer doing it 1/2 is better because the gas expands, but you could also get vapor lock. So do not fill it all the way if you want it not to overexpand and spill or give extra pressure in the tank. It is best to fill up your tank in the early morning VS. evening to due to expansion of fuel, you get more fuel to the dollar this way. Answer to add to the last anwser another thing is that weather its a urban myth or not it is said that when your gas tank is above half you will get better mpg Answer Another thing to consider is that the fuel in the tank acts as the coolant for the fuel pump motor (if it's an in-tank pump). Leaving the tank mostly empty all the time can cause premature pump failure.

PwrStroke

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Phoenix

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Message Posted: Aug 24, 2007 3:12:12 PM

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First answer by Ask Hutch Ask Hutch. Last edit by Paul2006.

Answer
The last answer is correct, with an electric in-tank pump never let it go below 1/4 tank.
Answer
It used to be advised not to let the fuel get too low in the tank. This was because dirt could lay in the bottom of the fuel tank, this dirt could then be picked up and block fuel lines and jets. Fuel these days is so well filtered that this is no longer a problem so it makes no difference when you decide to add more fuel. Answer
It depends on what you are trying to accomplish: 1- In the winter it is better to fill the tank ASAP to prevent moisture from potentially freezing the gas line and from running out of gas due to unexpected traffic or weather related issues. (Not an issue in PHX Az)

2- If you are trying to save on the extra weight of gas then fill close to empty.

3- If you are mixing lo and hi octane gas then do it at 1/2 tank.

4- In the summer doing it 1/2 is better because the gas expands, but you could also get vapor lock. So do not fill it all the way if you want it not to overexpand and spill or give extra pressure in the tank. It is best to fill up your tank in the early morning VS. evening to due to expansion of fuel, you get more fuel to the dollar this way.

Answer

to add to the last anwser another thing is that weather its a urban myth or not it is said that when your gas tank is above half you will get better mpg Answer

Another thing to consider is that the fuel in the tank acts as the coolant for the fuel pump motor (if it's an in-tank pump). Leaving the tank mostly empty all the time can cause premature pump failure.

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JumpinJimmyJack All-Star Author Detroit Posts:637 Points:174,685 Joined:May 2007	Message Posted: Oct 27, 2007 7:07:00 PM Ignore JumpinJimmyJack Report Abuse Buddy123, I think it is kinda hard and distracting to stop for gas when you're being chased or actively looked for by the police and couple of hundred angry villagers.
spikydan1 Sophomore Author New Jersey Posts:117 Points:134,690 Joined:Aug 2007	Message Posted: Oct 27, 2007 6:54:45 PM Ignore spikydan1 Report Abuse I always fill up at 1/4 so I never have to worry about running out of gas.
tlfh46 Champion Author Indiana Posts:8,778 Points:1,972,670 Joined:Jun 2004	Message Posted: Oct 27, 2007 12:24:09 PM Ignore tlfh46 Report Abuse Does it really matter.
Chazzer Champion Author Nevada Posts:10,231 Points:2,150,660 Joined:May 2002	Message Posted: Oct 27, 2007 10:58:26 AM Ignore Chazzer Report Abuse At a quarter full or half no matter. But not when it's almost empty too many impurities.
kssipe Champion Author Virginia Posts:3,376 Points:644,715 Joined:Sep 2005	Message Posted: Oct 25, 2007 9:48:22 PM Ignore kssipe Report Abuse i fill up either when empty on when prices are about to rise
AKTigger99645 Champion Author Anchorage Posts:5,937 Points:1,079,545 Joined:Mar 2005	Message Posted: Oct 25, 2007 5:26:43 PM Ignore AKTigger99645 Report Abuse I fill at 1/4 in the summer, and 1/2 in the winter.
buddy123 Veteran Author Pittsburgh Posts:399 Points:257,785 Joined:Sep 2005	Message Posted: Oct 25, 2007 5:16:18 PM Ignore buddy123 Report Abuse Petrothirst, use common sense. If somone likes your car and the tank is empty, don't you think they could stop at one of the 100 stations in the area and fill up???
shop18 Champion Author Buffalo Posts:4,258 Points:544,445 Joined:Sep 2005	Message Posted: Oct 25, 2007 3:28:43 PM Ignore shop18 Report Abuse I always want a full tank in case of emergencies
Petrothirst All-Star Author Los Angeles Posts:705 Points:146,055 Joined:Nov 2005	Message Posted: Oct 25, 2007 1:49:39 PM Ignore Petrothirst Report Abuse If you're planning on being car-jacked soon, it's best to keep the tank as close to empty as possible. This insures that your car will be left in close proximity to wherever it was taken and much easier to retrieve.
nikwv Champion Author Charleston Posts:1,992 Points:431,605 Joined:Sep 2005	Message Posted: Oct 25, 2007 1:38:30 PM Ignore nikwv Report Abuse half
JPGKC Champion Author Tampa Posts:4,419 Points:821,025 Joined:Sep 2006	Message Posted: Oct 25, 2007 11:38:22 AM Ignore JPGKC Report Abuse I have always filled at 1/2 tank.
cymivka Champion Author Los Angeles Posts:4,754 Points:1,146,620 Joined:Apr 2004	Message Posted: Oct 25, 2007 11:12:34 AM Ignore cymivka Report Abuse i hear it's not good to let the tank fall below 1/4, so i'd say 1/2 tank.
jayleno0NJ Sophomore Author New Jersey Posts:157 Points:25,475 Joined:Oct 2007	Message Posted: Oct 25, 2007 12:13:15 AM Ignore jayleno0NJ Report Abuse I fill when it's almost empty.
1996_ford_slurp Rookie Author New Jersey Posts:16 Points:9,370 Joined:May 2007	Message Posted: Oct 24, 2007 10:54:26 PM Ignore 1996_ford_slurp Report Abuse I never go over half a tank. with my 30 gallon capacity, a full tank weighs about 240lbs. that's almost 10 cinder blocks sitting in the back. in the winter I may fill up for better traction, but that's the only time. also: 1. the little electric fuel pump in the tank is in no immediate danger of overheating 2. gasoline freezes at -97F. a little moisture in pressurized fuel lines is not going to freeze enough to block the gas. unless somehow there was enough water, and it didn't mix with the fuel, and magically got pumped into the fuel lines unmixed. If it is still a concern, you can purchase methyl alcohol additives to remove moisture from the tank. 3. fuel tanks are not pressurized but the lines are, even when the car is off. older carburated engines do not stay pressurized. remember pumping the gas 2-3 times before starting that first hoopty you had in high school. [Edited by: 1996_ford_slurp at 10/24/2007 10:57:59 PM EST]
papaalex Champion Author Houston Posts:3,627 Points:588,000 Joined:May 2007	Message Posted: Oct 24, 2007 6:54:09 PM Ignore papaalex Report Abuse i fill it up at 1/4
nikwv Champion Author Charleston Posts:1,992 Points:431,605 Joined:Sep 2005	Message Posted: Oct 24, 2007 11:44:48 AM Ignore nikwv Report Abuse half
dwgt.net Champion Author Nevada Posts:10,591 Points:1,853,560 Joined:Sep 2004	Message Posted: Oct 24, 2007 11:15:44 AM Ignore dwgt.net Report Abuse To save money, fill it only when prices are rising.
Crackdaddy Sophomore Author Charlotte Posts:212 Points:320,670 Joined:Nov 2005	Message Posted: Oct 24, 2007 11:06:44 AM Ignore Crackdaddy Report Abuse I always seem to wait until the gas light is on and then see how far I can press my luck. Luckily (knock on wood) I have never ran out of gas...YET!
cv Champion Author Raleigh Posts:9,200 Points:2,082,805 Joined:Oct 2003	Message Posted: Oct 24, 2007 9:21:02 AM Ignore cv Report Abuse Personally I fill up when the tank gauge shows half full, I've always done that even when gas was $1.50/gal.
cymivka Champion Author Los Angeles Posts:4,754 Points:1,146,620 Joined:Apr 2004	Message Posted: Oct 24, 2007 8:18:39 AM Ignore cymivka Report Abuse i think 1/2 tank is good.
Ozman Champion Author Maine Posts:9,723 Points:2,115,305 Joined:Sep 2003	Message Posted: Oct 23, 2007 8:25:59 PM Ignore Ozman Report Abuse I run close to empty all the time - never had a problem with it....and rarely fill up.
trucker432 Champion Author Texas Posts:6,101 Points:1,173,015 Joined:Jul 2006	Message Posted: Oct 23, 2007 8:23:22 PM Ignore trucker432 Report Abuse whatever you want-Just do what you got to do!
nikwv Champion Author Charleston Posts:1,992 Points:431,605 Joined:Sep 2005	Message Posted: Oct 23, 2007 12:55:17 PM Ignore nikwv Report Abuse half
FuelPump Champion Author Los Angeles Posts:14,959 Points:2,229,890 Joined:Apr 2003	Message Posted: Oct 23, 2007 12:48:00 PM Ignore FuelPump Report Abuse Old habit from years ago when I lived in a cold climate, I always drive off the top half of the tank.
tlfh46 Champion Author Indiana Posts:8,778 Points:1,972,670 Joined:Jun 2004	Message Posted: Oct 23, 2007 12:41:16 PM Ignore tlfh46 Report Abuse Does not really matter.
racer3 Champion Author New York Posts:7,294 Points:1,477,300 Joined:May 2004	Message Posted: Oct 23, 2007 12:07:43 PM Ignore racer3 Report Abuse whenever you want
GatorGirll Champion Author Long Island Posts:6,296 Points:1,055,600 Joined:Aug 2005	Message Posted: Oct 23, 2007 10:47:31 AM Ignore GatorGirll Report Abuse depends on what the price is
cymivka Champion Author Los Angeles Posts:4,754 Points:1,146,620 Joined:Apr 2004	Message Posted: Oct 23, 2007 8:07:10 AM Ignore cymivka Report Abuse i think half at least.
sandy40 Champion Author Nova Scotia Posts:6,727 Points:1,337,860 Joined:Nov 2005	Message Posted: Oct 23, 2007 7:54:03 AM Ignore sandy40 Report Abuse I fill it at 1/2 full.
cucamping Champion Author Omaha Posts:5,797 Points:1,228,335 Joined:Jun 2006	Message Posted: Oct 23, 2007 7:35:31 AM Ignore cucamping Report Abuse I do it around a 1/4 tank.
BroncoFans Champion Author Utah Posts:4,401 Points:896,295 Joined:May 2005	Message Posted: Oct 23, 2007 7:17:05 AM Ignore BroncoFans Report Abuse WHAT EVER FLOATS YOUR BOAT...
srs_49 Champion Author Baltimore Posts:4,235 Points:459,520 Joined:Feb 2006	Message Posted: Oct 23, 2007 6:39:05 AM Ignore srs_49 Report Abuse Whatever floats your boat.
abeazar Champion Author Tampa Posts:12,535 Points:2,436,260 Joined:Apr 2003	Message Posted: Oct 23, 2007 6:24:24 AM Ignore abeazar Report Abuse Not sure!
Ratso Champion Author Ohio Posts:9,359 Points:1,510,820 Joined:Sep 2003	Message Posted: Oct 23, 2007 5:47:05 AM Ignore Ratso Report Abuse Arte49 has the answer ...whenever you have the cash !
Bus561 Champion Author Lexington Posts:10,423 Points:2,034,875 Joined:May 2004	Message Posted: Oct 23, 2007 5:21:04 AM Ignore Bus561 Report Abuse Fill it up at 1/2 as then it doesn't hurt your billfold quite as much.
arte49 Champion Author Fort Worth Posts:6,631 Points:1,519,775 Joined:May 2005	Message Posted: Oct 23, 2007 5:11:05 AM Ignore arte49 Report Abuse these days, whenever I have the money !!!!
SIPLOWGUY Champion Author New York Posts:8,338 Points:1,585,165 Joined:Sep 2005	Message Posted: Oct 23, 2007 4:40:29 AM Ignore SIPLOWGUY Report Abuse 1/4
TucsonGas1 Champion Author Tucson Posts:8,170 Points:2,003,130 Joined:Mar 2003	Message Posted: Oct 22, 2007 11:46:17 PM Ignore TucsonGas1 Report Abuse yes
jd808080 Champion Author Baltimore Posts:4,639 Points:1,026,455 Joined:Feb 2006	Message Posted: Oct 22, 2007 10:40:17 PM Ignore jd808080 Report Abuse I fill up whenever the right or back seat driver tells me to. (Saves a lot of arguing.)
Lum Champion Author Ontario Posts:13,878 Points:2,049,310 Joined:Sep 2003	Message Posted: Oct 22, 2007 6:25:42 PM Ignore Lum Report Abuse In the cold weather half is what I do
rjn5851 Champion Author Florida Posts:8,674 Points:1,815,730 Joined:Jun 2004	Message Posted: Oct 22, 2007 2:39:51 PM Ignore rjn5851 Report Abuse bout 3/4.....
jason54915 Champion Author Wisconsin Posts:7,972 Points:1,636,575 Joined:May 2004	Message Posted: Oct 22, 2007 2:33:29 PM Ignore jason54915 Report Abuse interesting
champr Rookie Author Virginia Beach Posts:33 Points:14,340 Joined:Aug 2005	Message Posted: Oct 22, 2007 2:27:27 PM Ignore champr Report Abuse Normally around 1/4 tank.
nikwv Champion Author Charleston Posts:1,992 Points:431,605 Joined:Sep 2005	Message Posted: Oct 22, 2007 1:37:11 PM Ignore nikwv Report Abuse Its better to fill up at 1/2 tank.
beemerguy Champion Author Kansas City Posts:17,818 Points:1,554,105 Joined:Oct 2005	Message Posted: Oct 22, 2007 1:01:43 PM Ignore beemerguy Report Abuse All up to the individual...we prefer to always keep the tanks full or near full, never having to take on more than three-four gallons when we stop. Sometimes we pay a little more, sometimes a little less but keeping the tanks full or near full takes advantage of dollar cost averaging and we're never negatively impacted to any degree.
Lengas Champion Author Gary Posts:7,227 Points:1,532,605 Joined:Nov 2004	Message Posted: Oct 22, 2007 12:44:15 PM Ignore Lengas Report Abuse There are pros and cons to 1/2 and 1/4 tank. If you fill up it will be a longer time before you fill up again if you go down to 1/4. If you only fill up to 1/2 tank you will get slightly better mileage because of lighter weight but will have to get gas more often.
ridinit All-Star Author Mississippi Posts:505 Points:288,400 Joined:Nov 2006	Message Posted: Oct 22, 2007 8:59:27 AM Ignore ridinit Report Abuse I don't think it matters.
Manolo1 Champion Author Miami Posts:3,064 Points:586,830 Joined:Jun 2007	Message Posted: Oct 22, 2007 8:53:00 AM Ignore Manolo1 Report Abuse Most of the time I fill up shortly after the reserve light comes on and I get 14 to 14.5 gallons in a 17 gallon tank, so I am comfortable doing that. As I bought the car new and use good gasoline I don't expect to have any problems.
cymivka Champion Author Los Angeles Posts:4,754 Points:1,146,620 Joined:Apr 2004	Message Posted: Oct 22, 2007 8:34:06 AM Ignore cymivka Report Abuse i hear it's good for the pump to keep it at least 1/2 full.
tlfh46 Champion Author Indiana Posts:8,778 Points:1,972,670 Joined:Jun 2004	Message Posted: Oct 22, 2007 3:40:38 AM Ignore tlfh46 Report Abuse Does not matter.