Draining a gas tank.

What is the easiest way to drain a gas tank? I am finally getting my jeep back on the road again after an engine rebuild. The last state inspection on it was from October of '03!!:gonnablow I bought it about 2 years ago and have slowly been going through the rebuild process. Just about everything is hooked back up and I am ready to try and start the motor for the first time but I need the tank to be emptied because there is no was gas that old can't be any good.

At first I was thinking about just droping the tank and removing the fuel pump and dumping it out from there. But then I started thinking about just removing the fuel line just before the fuel filter, turning the ignition to "Run" and just letting the fuel pump do its job and pump all of the gas out. Would this even work? Would there be any drawbacks to doing it this way if it will work?

Hallo Jeeper. You can run your pump by the pumprelay.
connect pin#30 and pin#87.:flamemad:

wim hoppenbrouwers said:

Hallo Jeeper. You can run your pump by the pumprelay.
connect pin#30 and pin#87.:flamemad:

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I know that there are alternate ways to run the fuel pump. My main question was whether or not using the fuel pump with out dropping the tank was an effective way of draining the tank.

VAwheeler said:

I know that there are alternate ways to run the fuel pump. My main question was whether or not using the fuel pump with out dropping the tank was an effective way of draining the tank.

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why drop the tank?

what year?

if you have an external fuel filter near the rear drivers side tire, just disconnect the fuel filter, attach a hose to the line coming from the tank and to a container and run the pump.

89xj said:

why drop the tank?

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At first I was thinking that in order to get all of the gas out of the tank it may need to be dropped.

89xj said:

what year?

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Damn it....I need to put the year and model in a signature.


90 XJ Sport. 4.0 I6

89xj said:

if you have an external fuel filter near the rear drivers side tire, just disconnect the fuel filter, attach a hose to the line coming from the tank and to a container and run the pump.

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This is the route that I have thought about recently and just didn't know if this method would get all or nearly all the gas out of the tank. I know on the late 80's F-150 there would still be well over a gallon of fuel left in the tank even after the fuel pump stopped pumping anything. I didn't know if anyone knew if the XJ's had the same type of issue with getting all of the fuel out or not.

When I drained the tank on my 90 a few years ago there was no motor in it and too many things were unhooked to hook a battery up and use the ignition. I hooked a battery up to the lead from the pump. The Nycopac connector will be marked A and B. B is the positive side if I remember correctly.

5-90 can correct me!

xjtrailrider said:

When I drained the tank on my 90 a few years ago there was no motor in it and too many things were unhooked to hook a battery up and use the ignition. I hooked a battery up to the lead from the pump. The Nycopac connector will be marked A and B. B is the positive side if I remember correctly.

5-90 can correct me!

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I just finished putting the motor back in. So all (hopefully) of the wires and hoses are back in the correct locations. I have been getting an itchy finger wanting to try and start it up but I have to get some good gas in it first.

Did your method get all of the gas out?


Thanks for the tip on the wires just in case I have something hooked up wrong I can still get the gas out this evening.

A leftover gallon will be well-diluted when the tank is refilled with new fuel. Don't forget to change your fuel filter out, too.

Jim www.yuccaman.com

VAwheeler said:

I just finished putting the motor back in. So all (hopefully) of the wires and hoses are back in the correct locations. I have been getting an itchy finger wanting to try and start it up but I have to get some good gas in it first.

Did your method get all of the gas out?


Thanks for the tip on the wires just in case I have something hooked up wrong I can still get the gas out this evening.

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Most of it, a little was left. The gas was about 3 years old. I filled the tank up, added some seafoam and put in a new filter. Started the new motor with no issues. Ran it for a month then put another new filter in. Thats been 2 trouble free years ago.

if there is only a few gallons in there, Just go get 5 gallons of premium and the mixture should be fine. at 12-15mpg, it will burn all out just testing the motor!

I needed to get the old gas out of my '82 Toyota truck. It had sat for at least 4 years not running. Instead of siphoning the gas out the old fashioned way I fashioned something else up. I ran a 3/8 clear hose into the tank after rmoving the filler neck. Drilled a 3/8 hole in the cover from an empty plastic washer fluid bottle. Put the hose through the hole and screw on the cap. By pumping the washer fluid bottle, suction was created and the fuel came out. I know that's really ghetto but it worked. Dropping the tank was not an option because it was rusted on really good. Hope that helps you....eace:

nonnie said:

I needed to get the old gas out of my '82 Toyota truck. It had sat for at least 4 years not running. Instead of siphoning the gas out the old fashioned way I fashioned something else up. I ran a 3/8 clear hose into the tank after rmoving the filler neck. Drilled a 3/8 hole in the cover from an empty plastic washer fluid bottle. Put the hose through the hole and screw on the cap. By pumping the washer fluid bottle, suction was created and the fuel came out. I know that's really ghetto but it worked. Dropping the tank was not an option because it was rusted on really good. Hope that helps you....eace:

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Nice... ain't nothin' wrong with a little ghetto. :cheers:

nonnie said:

I needed to get the old gas out of my '82 Toyota truck. It had sat for at least 4 years not running. Instead of siphoning the gas out the old fashioned way I fashioned something else up. I ran a 3/8 clear hose into the tank after rmoving the filler neck. Drilled a 3/8 hole in the cover from an empty plastic washer fluid bottle. Put the hose through the hole and screw on the cap. By pumping the washer fluid bottle, suction was created and the fuel came out. I know that's really ghetto but it worked. Dropping the tank was not an option because it was rusted on really good. Hope that helps you....eace:

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Did you happen to look at the bottom of the Toyota tank, near the front? There is a little thing called a drain plug. Remove it, and the fuel runs out! In case you ever need to do that again...

the problem i see is if theres any rust or water do you really want to run it through the pump. also it can also turn into a gum like substance put fresh fule into it break that stuff loose and have a burnt up pump/pluged line. if it were me I would pull the tank and look inside just to feel better