Excess tank pressure?
Thread Starter
Drifting
Joined: Jun 2015
Posts: 1,340
Likes: 753
From: Doctors Inlet Florida
Excess tank pressure?
I have a 70 Corvette with no emissions and a sealed gas cap. Lately when I take the gas cap off it is under a lot of pressure. I have my carb off for some repairs and woke up today with raw gasoline all over the garage floor coming out the fuel line.
Could my pressure valve at the top of the tank failed?
Could my pressure valve at the top of the tank failed?
Team Owner
Joined: Sep 2006
Posts: 31,170
Likes: 4,245
From: Westminster Maryland
Hi,
I'm quite sure 70-72 model year cars had a gas cap that's marked SEALED, and that sealed the tank.
You should expect some 'whoosh'.
The neck on the tank is designed with a 'ramp' and intermediate 'stop' that allows the cap to be turned to release the pressure and then the cap is turned the rest of the way to release the cap from the filler neck.
Have you tried to reach past the rubber boot to push on the button valve?
You should be able to push it in about a 1/16" and it should spring back on it's own.
Regards,
Alan
Just to the left of the filler neck.
I'm quite sure 70-72 model year cars had a gas cap that's marked SEALED, and that sealed the tank.
You should expect some 'whoosh'.
The neck on the tank is designed with a 'ramp' and intermediate 'stop' that allows the cap to be turned to release the pressure and then the cap is turned the rest of the way to release the cap from the filler neck.
Have you tried to reach past the rubber boot to push on the button valve?
You should be able to push it in about a 1/16" and it should spring back on it's own.
Regards,
Alan
Just to the left of the filler neck.
Last edited by Alan 71; Mar 29, 2018 at 07:54 AM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
With the carb off and the car in the garage he only forces working on the gasoline at night could be gravity. That means you have a fuel leak somewhere as the tank is not getting pressurized during the cooling night time but rather the pressure should be trending to a vacuum in that situation.
I believe even the non vented gas caps have a internal relief valve for both overpressure and vacuum. This is to protect the fuel tank.
Not sure why you think the tank builds pressure while in the garage. If it truly is then you have some kinda chemical reaction going on within the fuel tank - maybe you should car the fire department.
I believe even the non vented gas caps have a internal relief valve for both overpressure and vacuum. This is to protect the fuel tank.
Not sure why you think the tank builds pressure while in the garage. If it truly is then you have some kinda chemical reaction going on within the fuel tank - maybe you should car the fire department.
