Humvee Fuel Tank Overfill Causing a leak?

[Hummer Guy]

https://www.psmagazine.army.mil/News/Article/2549126/hmmwv-dont-overfill-fuel-tank/ I just seen this article and find it pretty strange. So, we should only be filling up to 3/4 of a tank? I had filled mines up last week and notice a small leak from the top, I thought my tank was possibly be cracked at the top.

On a 2nd note, have anyone ever installed that 17 gallon AUX fuel tank? If so, where is it installed at? I been looking at getting that myself but never pulled the plug on it because of how much it cost

 

[emmado22]

You ever fuel a HMMWV from a HEMTT fueler? it doesnt "click off" like your gas station nozzle.

Like anything else, use common sense, unlike some people in the Army.

 

[Coug]

aux tank gets installed behind the rear diff, so same location as the pioneer tool kit.

system is supposed to be sealed, because supposedly it can be run in 5 feet of water. If gravity is enough to make it leak fuel, then something isn't right.

 

[juanprado]

I have the complete kit as it is extensive- Additional gauge and wiring, Extra filler neck, cap, and bucket, specific bumper brackets, Fuel Lines, tank etc

and "might " consider letting it go. Also I am down the road and I think we can work out a handoff... If interested, send me a p,m

 

[Hummer Guy]

I have the complete kit as it is extensive- Additional gauge and wiring, Extra filler neck, cap, and bucket, specific bumper brackets, Fuel Lines, tank etc

and "might " consider letting it go. Also I am down the road and I think we can work out a handoff... If interested, send me a p,m

For some reason, I thought that connects to the main tank, so its kind of like the H1 AUX with being a completely different tank?

 

[papakb]

It's a well known fact that when the coupling between the filler neck and the tank either loosens up or cracks from dry rot the tanks leak when filled. Get up under the vehicle and check the hoses and clamps. Remember some of these trucks are now going on 37 years old and rubber doesn't last forever especially when it sits in the sun day after day.

 

[juanprado]

I am not familiar with H1, but is a separate independent tank with its own fuel line and vent lines plus filler neck. I have not looked at the install manual recently if I recall 150 pages or so but seem to remember it has a valve and switch but I am foggy on that detail.

 

[Mullaney]

https://www.psmagazine.army.mil/News/Article/2549126/hmmwv-dont-overfill-fuel-tank/ I just seen this article and find it pretty strange. So, we should only be filling up to 3/4 of a tank? I had filled mines up last week and notice a small leak from the top, I thought my tank was possibly be cracked at the top.

On a 2nd note, have anyone ever installed that 17 gallon AUX fuel tank? If so, where is it installed at? I been looking at getting that myself but never pulled the plug on it because of how much it cost

.
Kinda have to agree with the rest of the guys...
Either a loose clamp or dry rotted hose on the filler neck or on the tank itself. (or both)

 

[Maxjeep1]

Square rubber gasket for the plate that sits on top of the tank. I was able to take the inspection cover off of the body and I could see cracks in it. Probably other things are leaking too but I had a waterfall on both sides of the tank…

 

[Retiredwarhorses]

Square rubber gasket for the plate that sits on top of the tank. I was able to take the inspection cover off of the body and I could see cracks in it. Probably other things are leaking too but I had a waterfall on both sides of the tank…

the filler neck rubber is notorious for failure after year of having Fuels sit in the hose and soften it up, the clamps loosen up and you have leaks. I probably do a fuel tank once a month, never seen the top plate leaking it’s always a filler neck issue, you will see cracking on the exposed edge of the top plate gasket, but that doesn’t seem to extend inwards to the entire gasket. Parking on a driveway after filling up will definitely test your tanks worthiness.