Gas tank pressure?
I'm in the final stages of getting my 3+ year CJ buildup complete, and have a question about pressure building up in the gas tank. I put about 11 gallons in the tank (4wdh extra capacity 22 gallon tank) to check the fuel gauge reading and to have plenty to get it up and running. I am using the stock CJ filler with the vent hose, but the gas cap is a lockable one and is not vented. I also plugged the two holes on the driver side of the tank that originally had lines for emissions.
During the day, I hear a noise that I swear is coming from the gas tank. The best way to compare it is to thumping an empty barrel with your hand. Almost a "doing" sound. When I take the gas cap off, there is a whoosh of pressure, but nothing extraordinary.
My question is if I should somehow vent the tank to prevent what sounds like expansion and contraction with temp changes or just leave it alone. I figured I could look for a vented cap or take one of the plugs out and run some type of vent line. Thanks for any help!