Last time I filled up there was a LOT of pressure in the fuel thank. I haven't looked closely, but it may have made the top of the tank bulge up a bit.
Probably the previous time I filled up I tried too hard to get it as full as possible. There as no air cushion to absorb the fuel expansion.
I have a one way valve in the vent tube to let air in but not out.
I am wondering if I should remove the valve.
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I would guess yes.
definatly remove it. bill
Mike--if you're traveling on the road, fill it to the max and don't worry as you will be using enough gas right away to prevent any pressure buildup.
If the car is going into the garage or just sit in the driveway after filling up, leave some room for expansion.
I added a one way valve to my car so that air could get into the tank but no gas would be let out---I was smelling fumes allthe time and the one way valve solved that.
My 2 cents worth.
The check valve can cause real problems in warmer climates.
Extend the length of tubing on the filler neck, make a 2-3 round coil then run the tube down the right wheel well. Install a gas filter on the end with the flow arrow pointed upwards.
If you have an electric fuel pump, install an on-off switch. Make sure you turn off the pump a few seconds before you turn off the engine. High pressure in the tank can lead to fuel pressure in the carbs - not good if the car is off and sitting in the garage.
You could use an open rollover valve like this: http://www.speedwaymotors.com/...Vent-Valve,5848.html
But as Jack mentioned, you will get a gassy smell because it's open all the time. And if you're allowing so little room for gas expansion in the tank, it will drip out the hose onto the floor but at least won't bulge the tank. Ideally the vent hose from this valve would run to a vented expansion tank to catch the overflow, but still allow the tank to breath.
Easiest is to simply not fill the tank completely full if you're not going to drive it right away. A quart of empty space is enough to account for 30* F of thermal expansion for 10 gallons of gas.
That's why I NEVER used one. No means for expansion. The pressure usually starts leaking at the cap with a valve installed. Your cap must seal REALLY well. I just run the vent tube in a high loop before it exits the trunk thru the trunk wall and down to the bottom of the pan.
