Leaking fuel after fill up

diezelraccoon · Jun 26, 2024

Wanted to try posting this again in a different forum because I really didn’t get much feedback.

I pulled into the gas station yesterday and filled up my 03 Tahoe. I squeezed in another buck or so after it stopped and then I heard and saw a bunch of gas leaking out from under the vehicle down from the left frame about midway under vehicle. Took at least 10 minutes for it to stop. It’s clearly coming from somewhere above the tank. Does anyone know what might be causing this?

SilverSport · Jun 26, 2024

over filled the gas tank...it is inadvisable to top off the fuel tanks any more as the gasoline is pushed into the charcoal canister and evaporative components causing issues or leaks...

good luck with your Tahoe

Bill

OR VietVet · Jun 26, 2024

Welcome to the forum from Oregon.

Like @SilverSport said. Stop overfilling the fuel. It shuts off when it does for a reason. You may have a fill hose or evap component that has a leak, any CEL's? You may have also now damaged some evap components.

Fless · Jun 26, 2024

No reason that a solid fuel tank and pump would leak other than a fault; the tank goes under light pressure and vacuum regularly so most times the system is sealed. You likely have a cracked fill tube or other component that could cause a fire. Get it inspected and repaired, by a shop if you don't feel capable.

And, like others have said, don't overfill it in the first place. Repair the cause and move ahead.

Marky Dissod · Jun 26, 2024

diezelraccoon said:
I squeezed in another buck or so

Stop it. Gasoline / petrol expands quite a bit as it warms up,
and the EVAP system is meant to absorb gasoline VAPORS.
When you squeeze in over a dime, you force the EVAP system to absorb liquid gasoline.

Eventually the charcoal in your charcoal canister will escape the canister, and
you will find carbon chunks in your vapor lines, maybe even your tank.

noodlesandsam2 · Jun 26, 2024

Even if you filled to the top, and hit evap, on a healthy system, a leak for that long is not normal behavior. I've got 22 years of T800 life, and the leak would make me look at the fuel pump seal to the tank. Do you have any Service Engine codes - Evap errors would trigger the SES light.

Matthew Jeschke · Jun 26, 2024

Crawl under your rear driver side quarter panel behind the tire and below the fill spout. There's two rubber hoses running back to the top of the tank... One is a fill and I think the other is a vent?

Check to make sure the fill doesn't have any cracks. Otherwise, I'm with @Fless maybe a leak somewhere. I've been fiddling around with my tank, evap, and fuel system for months now for better or worse, I'm quite familiar with it. Feel free to ask anything about how to take it apart as I'm sure others here would know as well.

noodlesandsam2 · Jun 26, 2024

I did it all on the 01 1500 - Fuel pump - 3 times in 270K, the filler behind the gas door, all the way to the tank, the steel lines, the plastic lines, the evap thing above the rear diff. I never had it leak for as long as he said. That's like driving a grenade.

Leaking fuel after fill up

diezelraccoon

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SilverSport

Full Access Member

OR VietVet

Multnomah Falls

Fless

Marky Dissod

Full Access Member

noodlesandsam2

Member

Matthew Jeschke

Full Access Member

noodlesandsam2

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