Could have blown up both the car and the house.

Hello everybody.

We had some really hot days here like a week ago or whatever, 110, and the Dart that was sitting outside the house started to smell gas.

Started the car, drove out of the driveway to place it out in the street, and suddenly I see a wet and shiny spot that would have been under the tank when the car was parked. Drove it up again, and opened the gas cap, and it was a lot of pressure in the tank. After letting that out, the dripping of the gas stopped, and have not happened again.

So, I can not live with it like this. The cap is not vented. And from the service manual it is not supposed to be either. There is a little tube from the top of the tank and up to the neck just inside the cap, but I assume that is for letting air out of the tank itself while filling at the gas station. It does not look to me as a tube that is supposed to let gas fumes out, because then it will pretty soon be unbarable back in the trunk, and inside the car too at some point.

So, what is missing here ? I have been thinking if I remove the rubber gasket, it will not keep the pressure in the tank, but then the cap will actually be vented, and it is not supposed to be that.

I put a new rubber gasket / seal on the cap last year, the old one was in pieces. I used 1/16 nitrile rubber sheet for that job.

Bill