What Causes Fuel Tank Collapse?

[OBX]

Experienced “fuel starvation” symptom of reduced power requiring increased throttle to maintain speed. Was able to make the trip back to my shop, but just barely. Humvee still starts immediately, idles without a problem. Was looking under the truck today and much to my surprise, noticed the fuel tank collapsed. Opened fuel cap and tank did not go back to original shape.
Lateral scrapes on fuel tank and frame rails are from the truck being lifted by fork lift at the GovPlanet yard (I witnessed this). Tank was not collapsed at that time.
Any ideas what would cause the collapse? For the curious, this is an 1152A1 #347XXX, 300 total miles since new. I’ve owned it for two years, tank collapsed last week when it experienced “fuel starvation”.

 

[Coug]

There is a fuel tank vent that comes up near the air filter intake. It's just a hose with what looks like a fuel filter sitting on the end of it.
If the fuel tank vent gets plugged it could possibly cause that.

 

[Milcommoguy]

You got one hell of a good fuel pump. Now YA going to put the air compressor to it and maybe pop it back out.

Damm that sucks, CAMO

 

[Retiredwarhorses]

Never in 30yrs anything like it…that tank is hard as hell.

 

[OBX]

Never in 30yrs anything like it…that tank is hard as hell.

I have a NOS fuel tank to replace it with, but still need to determine the cause. Will start by inspecting the vent line as suggested by Coug. No doubt the fuel pump is a good one, as CAMO said. One thing for sure…the entire fuel system is air tight! This is one for the books if even Steve/RWH hasn’t had a tank collapse.
Will keep everyone posted.

 

[Retiredwarhorses]

I have a NOS fuel tank to replace it with, but still need to determine the cause. Will start by inspecting the vent line as suggested by Coug. No doubt the fuel pump is a good one, as CAMO said. One thing for sure…the entire fuel system is air tight! This is one for the books if even Steve/RWH hasn’t had a tank collapse.
Will keep everyone posted.

there is an anti-roll over valve that the vent line connects too, you should replace that and blow the vent line out with compressed air as well, the vent filter you can pull off and just see if you can blow through it.

 

[dilvoy]

Could be forklift damage.

 

[OBX]

Could be forklift damage.

Thank you for the suggestion but the forklift scratches are superficial and two years old. The tank collapsed just a few days ago.

 

[m1010plowboy]

Was it anywhere near the Titanic? That will never happen to most of us. The ladies can't get us to vacuum. I thought this might be a rare occurrence but it happens. https://rennlist.com/forums/928-forum/488155-fuel-tank-imploded-not-catastrophic-2.html

One fella took his tank in the shower with him, filled it with hot water, gave it a hot blow with a hair dryer and it's all fixed. Soon they'll be married.

The old Early Deuce fuel cap had 3 settings. One for Fording, one for regular running and one which is used the most, open for more filling.

Is the HMMWV set up with a Fording Fuel Cap?

 

[Mogman]

Was it anywhere near the Titanic? That will never happen to most of us. The ladies can't get us to vacuum. I thought this might be a rare occurrence but it happens. https://rennlist.com/forums/928-forum/488155-fuel-tank-imploded-not-catastrophic-2.html

One fella took his tank in the shower with him, filled it with hot water, gave it a hot blow with a hair dryer and it's all fixed. Soon they'll be married.

The old Early Deuce fuel cap had 3 settings. One for Fording, one for regular running and one which is used the most, open for more filling.

Is the HMMWV set up with a Fording Fuel Cap?

I believe all the HMMWV caps are sealed, it depends on a vent line to vent the tank.

 

[Mogman]

Reminds me a story going around the dealership where I worked in the 70s
A guy buys a VW Rabbit diesel, fills the tank and drives to Corpus Christi, around 130 miles, he can only get a little over a gallon of diesel in the tank, drives back to SA and again can only get a little over a gallon in the tank, thinks he has a vehicle with the best fuel economy in the world, a few days later it quits, they tow it to the dealer where they discover the fuel tank has been sucked flat!

 

[thoner7]

Was it really hot one day then put away and checked on a cold day? Happens to my non-vented gas cans all the time

 

[SmartDrug]

They don't think it be like it is, but it do.

 

[juanprado]

suction cup will take care of that......

 

[OBX]

there is an anti-roll over valve that the vent line connects too, you should replace that and blow the vent line out with compressed air as well, the vent filter you can pull off and just see if you can blow through it.

Removed vent line valve and found it to be completed clogged. Truck now runs fine. Will change out the fuel tank when I run out of other things more important to complete at the moment. Thanks to all for your input.

 

[Milcommoguy]

So... you are saying that the fuel pump caused the tank to for a better word.... imploded the way it did?

That's a hell of a pump or a clog, CAMO

 

[Mogman]

Vacuum is powerful stuff!!

 

[Milcommoguy]

Vacuum is powerful stuff!!

Yes it is... But haven't seen or heard of this before in a HumV. Not saying it could not have happen this way. Those cheesy fuel pump lucky to draw fuel up... Just saying.

To have that happen really sucks, CAMO