I have a 1998 Chevy Blazer 2 door with the 19 gallon tank. Recently I've encountered a problem where when I'm at the gas station and let it fill up, it overflows past its limit and what seems like 1-2 gallons of fuel start spilling onto the floor directly under the fuel tank. I have looked around and heard that a vent valve may be the issue but it seems that only the 4 door tanks have a dedicated vent valve, unless I am mistaken of course.

For further explanation, I went to the gas station with roughly 2 gallons left in the tank. I let the station fill up the tank until it automatically stops as one would, which to my surprise gas starts spilling onto the floor directly under the fuel tank. Not at the filler hose. and the gallon counter says 19.075, contrary to the tank being only 19 gallons and I got there with 2 gallons already. I hope this makes sense.

 

On my 4dr there are two hoses that enter the tank. I imagine a similar set up on yours.

The 2"ID hose is the one through which the gas fills the tank. Next to it is a 3/4" or 1" ID hose that connects to near the inlet where you put in the gas pump nozzle.

I could your symptoms being caused by this smaller hose at the tank being disconnected or having a hole in it.

Does the diagram here look like what you have?
​​​​​​​https://nemigaparts.com/cat_spares/e...t/03/ts03-541/

Hopefully the leak is not because of something harder to fix.

 

if your in the rust belt?,,i did my 98 got nos tank and new lines from gas tank RENU

 

This is a long shot but maybe the ring that holds the pump gave. Therefore, filling the tank displaces the pump and overflows the top and around the sides of the tank. I just took my tank apart, I have pictures of the filler neck. I noticed the filler tube has a check ball.

 

Thank you all for your advice and sorry I went silent on this thread. It turned out to be my O-ring on the fuel pump housing. It was too large and didn't seal properly. Replaced it with a brand new one and it is fine now.

 

Glad you got that taken care of.