gas leaking at the top of the EVAP charcoal canister

[Tahoe97]

Forum members: Recently on my 97 Tahoe I noticed gasoline under the front of the vehicle on the driver's side, directly below the EVAP charcoal canister which is right up next to the radiator. Popped the hood and noticed the charcoal canister had gasoline pooling on top and dripping down the sides. Gas tank was full. No check engine light and no codes upon a scan. In June, 2024 I replaced my vapor canister purge vacuum switch ([AC Delco 212-578?] the one with the vacuum line coming from the canister and with the electrical connection to the PCM I believe) Today I disconnected that vacuum line at both ends and blasted compressed air throught it, no obstructions. I believe this switch connects to the purge valve [AC Delco 214-628?] which is mounted on the intake manifold. I have never replaced that part. In the 29 years of ownership of my Tahoe I have never seen gasoline on top of my vapor canister. Any ideas on what could be causing this? Thanks!

 

[exp500]

Overfilled Tank is first guess. You could somehow rig up a container inline to check if fuel is always there before charcoal can.Testing vac and purge while it is installed. Much better than a mouthful of gas.
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[Marky Dissod]

Recently on my 97 Tahoe I noticed gasoline under the front of the vehicle on the driver's side, directly below the EVAP charcoal canister which is right up next to the radiator.
Popped the hood and noticed the charcoal canister had gasoline pooling on top and dripping down the sides. Gas tank was full.

Overfilled Tank is first guess.

Mine too.
2nd guess: whatever is supposed to stop liquid petrol from getting into the vapor lines / vapor canister has been 'defeated'.