Obstructed gas fill vent



How do I clear a obstructed gas tank vent on a 2000 300M? Recently the gas fill nozzle did not shut off and overflowed. Evidently gasoline went down the vent tube, and since then we can only fill gas tank a trickle at a time. How do I clear the vent?


sounds as if fill valve went south,vent valve is for evap sys only.


the usual problem is by overfilling, the charcoal cannister gets over saturated, thus the lousy filling.

the usual repair is to replace the vent system cannister.


Have you examined the gasoline fill tube for obstruction? If the gasoline did fill the vapor line, it might be possible to disconnect that line (hose?) at the charcoal canister and let it drain; or, if the line is open to the gas tank (no valves, etc.), to use very low pressurized air to blow through the line to the tank to clear it.
As a work-around, you could stick a small tube down the fill tube to act as a vent. As you put in gasoline, the tube would vent, and the gas tank would fill.


Forget the vent line and canister. There is a check ball in the fill tube to prevent spills in case of a roll-over accident. When you over-filled the tank, the ball floated up and got stuck in the fill pipe, blocking it off. Shove something flexible down the filler pipe, a 3/8" plastic hose or rod works well, and see if you can’t dislodge the cork or plastic ball that’s blocking the fill pipe. Usually, they will drop down into their normal position and the problem is solved…


We have tried your suggestion, and it worked. We have been able to fill the gas tank as normal. Thanks for your reply!!! You saved us from a big headache. Bless you. Thanks again.


This thread needs to be bumped to the top regularly. The original question is one of our most frequent, and it is rare that anyone ever gets back to us with the happy message “It worked!” Thanks for the report, brooks, and well done to Caddyman.

I hope that all of the charcoal canister theorists take note. I never trusted that glib explanation.


Brooks is outstanding! Brooks responded! Now, if we could only think of an RSVP (an acronym for French, “Answer back, will yah, please?!” award…?