Fuel Tank Leak 2001 Suburban 1/2 ton 5.3

Frank Sub · September 29, 2006

When I park with a full tank of gas, nose down hill I get a small amount of fuel leakage out of the top of the tank, which drips over the front left edge of the tank. At about 3/4 of a tank the drip stops. This is a new problem which started at about 45K miles (currently 50K). Anyone know where the leak is, and what the fix is?--Frank Sub

Frank Sub · October 3, 2006

In doing a little investigting regarding my down hill gas tank leak, I believe there may be a pressure release vent/valve on the top of the tank. Can any one confirm this??--Frank Sub

NothinButBowTies · October 3, 2006

My 72 K-5 did this really bad. I always filed it under "sh*t happens".

redvett · October 3, 2006

My 72 K-5 did this really bad. I always filed it under "sh*t happens".

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Your old K5 Blazer has no comparison between it and a 2001 vehicle of any brand. There should be NO fuel leaking from the vehicle and should be checked out.

crazymjb · October 4, 2006

The only thing on the top of my 96 tank is the feed, return, and emmisions pipes, than the two filler neck hoses. It would be "unsafe" to have a tank that intentionally leaks.

My guess is that the fuel pump setup may have a leak around it. I am not sure what is used for the gasket around that. It is also possible, though less likely, you have a crack somewhere. It is unlikely it is the filler neck as you would likely notice a leak when fueling. Your best bet would be to either pull the bed or drop the tank. Pulling the bed with a few friends may be easier because it doesn't require you to disconnect everything.

Oh, how steep does the grade have to be?

Mike

Frank Sub · October 4, 2006

Hi crazymjb--It's a Suburban, so I guess I'll have to drop the tank.

The grade in the driveway is about 15 degrees.

Frank Sub

bdeboer · April 16, 2007

Frank Sub, did you ever find your problem? I have been smelling gas in the garage when mine is over 3/4 tank.

C & A s Dad · April 16, 2007

Frank, I am assuming you have checked the two hoses coming into the back of the tank. After my dealer replaced my fuel gauge sensor, I had a small leak. They had not tightened the clamp on the smaller of the two hoses. I tightened a couple of turns and that fixed it.

bdeboer · April 17, 2007

I took off the plastic shield that is below the tank, and fuel does seem to seeping from the flange or lines where they enter the top of the tank near the drivers side center. I couldn't see up there without a mirror or dropping the tank to locate the specific problem.

bdeboer · April 19, 2007

Does anyone know if there is anything to watch out for when dropping the fuel tanks on the Suburban? Are the fuel lines/electrical connections long enough to reach the ground?

bdeboer · May 4, 2007

Update: The fuel sending unit rusted on mine and caused the leak. The mechanic doing the work had to cut the quick disconnects off there was so much corrosion he couldn't get the collars to slide.