Some Soldiers are overfilling their HMMWV’s fuel tank, causing fuel to leak from the top of the tank.
Don’t overfill the fuel tank! Be sure to turn the rotary switch to RUN so you can watch the fuel gauge while filling the tank. Like it says in TM 9-2320-387-10 (Sep 12), avoid fuel spillage by filling the tank only to 3/4 capacity.
Also, fuel shouldn’t be coming out of the gaskets on the tank. There’s a vent that allows the fumes to escape. But if it’s plugged or crimped, the gas buildup can cause the tank to leak. Contact your field level maintenance to replace the damaged parts.