Fuel bubbling???

bandit · Jul 22, 2012

I go up the road and fill 5 gallon cans with non ethanol gas. I was filling up the tank today with one of the 5 gallon cans and some lead additive and happened to notice there is a bubbling noise coming from the tank filler spout after pouring gas in. It is not the sound of gas trying to go down the tube but rather more of a boiling/bubble type of sound inside the tank(it is not boiling). Noise went on for 15 minutes or so but finally stopper. What the heck is that??

I should add that this is a newer tank. Got it about two weeks ago.

Sixer · Jul 23, 2012

Vent blockage? Neighbor siphoning out as fast as it's put in?

Jim Bob The Dancing Bear · Jul 23, 2012

It shouldbe as Sixer said. Check your vent hoses and tube for any blockage. I suggest doing this with very little gas in the tank. It really sucks getting drenched in gas.

coloradodave · Jul 23, 2012

Sixer said:
Vent blockage? Neighbor siphoning out as fast as it's put in?

I go with the neighbor. He's a really small guy and kind of green around the gills.......

bandit · Jul 30, 2012

I don't think it is the vent tube. My 70 Charger has only one. It is a line that comes off of the fuel filler tube at the top. The tank was not full enough to make it up to the vent tube to create any blockage and the cap was off so it had plenty of air to release pressure. I recently replaced the tank so know there is nothing more to it. Pretty simple. The filler tube itself is split into two sections to allow air passage over the top portion of the tube but again the tank was not full enough for this to be a factor. It also was not the sound of fluid bubbling down. Very different. This was a very distinctive boiling type of sound. Like a lot of rapid bubbling.

Haha, no the neighbors do not have access.

440roadrunner · Jul 30, 2012

The early cars with carbon can vent systems has a separate can up in the trunk area, with a bunch of tubing from the tank going to it, as well as the tube up to front to the carbon can system

Later cars had a sort of "?dome?" built into the tank I think to prevent overfill. It would slowly let gas into the dome. I've forgotten the details. I may have a drawing of it around here.

The 72/ early system

bandit · Aug 6, 2012

Mine has none of those extra vent tubes or charcoal canisters. Just the vent tube on the filler neck that goes down beneath the trunk floor and out(not connected to anything). I had it apart a little bit ago so know there is nothing else to it. The fuel line comes out of the tank, goes through the electric fuel pump(last owner put it in) then right to the carb after going through a fuel filter. No other lines leaving the gas tank.

I heard the bubbling noise again the other day when I put more gas in it. Definately not air trying to bubble/gurgle down. Very odd. You'd swear the gas was boiling in there but nothing was hot. Can that lead additive be creating some kind of reaction with unleaded, ethanol free gas?? This last time I added gas it was just straight gas and I heard the bubbling but the additive is still in the tank from the last fill up I'm sure. I am out of ideas.

Dako · Aug 6, 2012

If you think it may be the additive, why not try adding the additive to the gas while it's still in the gas can to see what THAT does?

bandit · Aug 6, 2012

Just added some to one of the 5 gallon cans, and nothing. I wonder if the new metal in the tank is creating some kind of reaction........

Hemi Rebel · Aug 7, 2012

I wonder if its fuel in the line near the engine getting hot and pushing back into the tank.

Fuel bubbling???

bandit

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Sixer

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Jim Bob The Dancing Bear

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coloradodave

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bandit

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440roadrunner

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bandit

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Dako

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bandit

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Hemi Rebel

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