Don't wait until the gas tank is empty before filling up?

Question

i've been told time and time again not to let the gas meter hit "empty" before filling up. so far i've been listening to the advice, but i've never really understood why that's the case.

they tell me the impurities and sediments in gas settles to the bottom of the tank and it's bad for it to run through the engine but where do all these impurities come from?? certainly not from the gas itself because to my knowledge the distillation process is very clean and efficient.

my next question is, doesn't gas get sucked up into the engine from the bottom of the tank anyway? wouldn't it be a similar mechanism like drinking water out of a straw, where you take up liquid from the bottom of the container? if so then i really don't see a point in filling up before the tank is empty. having excess gas that's not used is like carrying a permanent dead weight in the car that doesn't do anything...

some clarification would be appreciated!

Answer 1

There is a danger of damaging the catalytic converter

Answer 2

I wouldn wait until my gas tank is empty, because of all the c**p in the bottom and the dirt and all of the water and other impurties that will run to the engine, you need to always put gas in your tank before it goes below 1/4 a tank, that way you will leave all of the bad stuff in the bottom of your tank.

Answer 3

chris s,, has it right, fuel pump is cooled by the fuel in tank,,continuous running low can cause pump failure. even worse if you idle a lot .it cost $300 to replace and happens all the time---also h2o condensation is much worse..and even worse if you buy gas with alcohol in it...alcohol absorbs water....the ideal would be a full tank all the time if you don't drive very much

Answer 4

ok check this out. im a mechanic, the whole reason i dont run my tank too low is because if you run your car out of gas your fuel pump cant suck gas up and loses it prime and could possible in time ruin your fuel pump because it over works trying to suck gas instead of priming up quickly like it is designed to do. and yes your tank builds up trash there is now way them fuel tanks in the ground at the fuel stations and the trucks that deliver the fuel are perfectly clean. you never heard of a store selling bad gas, it happens all the time. but your cars is designed to catch trash with a fuel fitler and your pump also has a screen at the bottom of it to keep trash out also. so there you have it, i would recommend to get at least a quarter of tank of gas in your car at all times. you never know when you might have an emergency and dont have time to stop at the store. and fuel filters do get clogged up

Answer 5

there is a layer of gunk that builds up on the bottom of the tank, if you have always let the fuel run down really low you won't have this problem,but if you always keep a decent amount of fuel in it it will develop this layer in the bottom, so when you start running it down low it sucks up all the c**p and starts blocking all your fuel filters (my mother tired this, you couldn't see through the filter and the pump was screwed)

in the cars we own, the fuel pump is cooled by the fuel in the tank so if you have very little fuel in the tank there is nothing there to cool the pump and it then burns out.

disregard this if its irrelevant!!

have a good one mate!!

i assume you are talking about unleaded petrol kind of fuel in aus we call it petrol rather than gas, we call LPG, gas so its very confusing!!  

Answer 6

I've never heard this "reason"... hate to think what kind of gas you think you're getting if you worry about impurities in it.  

The reason not to run until empty is far more simple.  If you run it to the last drop, you stand a much better chance of misjudging and running dry before you get to a station.  Or, even more likely, running into something you can't foresee, such as a traffic jam on the way to fill up, that drains your tank before you get there; or a disaster where everyone is trying to fill up at once (I ran into this personally when Hurricane Rita approached... 1 gallon of gas left, and 5 stations in a row were out of gas because everyone was filling up to flee).

Answer 7

Hello

The big oil industry protect their interests by hiding new technology.

I recommend you visit:

http://w3t.org/c/saveongas

This sites will open your eyes regarding the doubt about gas saving and how to help the environment

Take good care,

Answer 8

for one not waiting until you are on empty saves you from running out of gas.. another reason which I just found out after a local investigation.... the amount of gas you think you put in your car isn't always accurate.. the thermometers in the fuel tanks at the stations are regulated for 60 degrees so when it is hot outside the fuel expands and you are charged for lets say 20 gallons when you are really only getting 18.. and that the best time to fill up is either first thing in the morning or at night when the temps are lower.. you will paying for  your gas rather than air.

Answer 9

If youve been told by everyone to do this, then why not follow their advice and do it?

Ive let the tank get empty before years ago, and always waited till the last minute to fill it up. Because of this i had more than several instances where I was out of gas and had to walk or call for a ride to get gas. If you dont have a gas tank in your trunk then your screwed into buying one or having to wait till your friend comes to lend you is.

It also bad because if you run on empty your running it on no gas. Thats like running a a water based machine with no water. Sooner or later itll stop working or overheat and bust.

Do you want that to happen to your car? Then follow instructions.  

Answer 10

well there are many reason that its not good ... you might have to walk is best one.... more trash with tank almost most emplty than gas... tank will sweat more cuusing more water and rust... fuel pump as the car gets older wil have to work harder.... been driving over 40 yrs and working on cars just about as long.... it dont matter if you run out of or low.... just not wise thing to do.. its your car and your shoes

Answer 11

the impurities and sediments come from the gas itself. sometimes the gasoline is carrying some amount of water that can create impurities and sediments. then, the water will mix with the hydrocarbon gas created from the remaining gasoline. it maybe look dangerous, but it's safe in small amounts because these will filtered by the fuel filter. it's important to check and clean your car's gasoline tank periodically. in some type, there is a Charcoal Canister that will transform the hydrocarbon gas in the tank into gasoline again and transferred to the engine.

Then, the gasoline is distributed to the engine using a fuel pump. there are two types : mechanical type and electric type. many modern vehicles that use electronic fuel Injection use the electric pump. the mechanism is like a water pump used in homes. the fuel drained from the tank through the fuel hose line, then enters the fuel filter to clean the fuel from dirts and sediments. after that, the gas will pumped to carburetors or injectors using the fuel pump