Pressure in gas tank - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Southpa · 05-06-2004, 10:01 PM

I seem to be building up lots of pressure in the gas tank now that some warmer weather is showing up. WHOOOOOSH! when I pull the cap off. I've been asking around about vented gas caps for these trucks but no one seems to carry or even heard of them. I think someone mentioned drilling a tiny hole in their cap, so pressure would be regulated a bit at a time. Any problems with that?

Longhorn Man · 05-06-2004, 11:46 PM

You tried just getting one for a 70 truck? I did that a few years ago and they gave me the right one...probably auto zone, I know it was at a large parts store chain, a smooth chrome stock looking cap, never had any problems with pressure build up with it.

chevymad · 05-07-2004, 12:26 AM

The Napa "california" truck cap has a pressure relief at 3psi. They've got a check valve that lets air in no problem too. The regular caps have a one way check valve, lets air in but builds huge pressure like you're talkin about. I got tired of smellin gas in the cab when I had one. So much pressure would build the tank would actually start springing out. The california cap cured that.

Hooter · 05-07-2004, 01:14 AM

my tank would puff up so bad on th 74 that it would force gas out of every crevace, I got a vented cap from Lordco from my 69, there should be a Lordco in Victoria i would assume, they will have the right cap

05-06-2004, 10:01 PM	#1
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,409	Pressure in gas tank I seem to be building up lots of pressure in the gas tank now that some warmer weather is showing up. WHOOOOOSH! when I pull the cap off. I've been asking around about vented gas caps for these trucks but no one seems to carry or even heard of them. I think someone mentioned drilling a tiny hole in their cap, so pressure would be regulated a bit at a time. Any problems with that? __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

05-07-2004, 01:14 AM	#4
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	my tank would puff up so bad on th 74 that it would force gas out of every crevace, I got a vented cap from Lordco from my 69, there should be a Lordco in Victoria i would assume, they will have the right cap __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

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05-06-2004, 11:46 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	You tried just getting one for a 70 truck? I did that a few years ago and they gave me the right one...probably auto zone, I know it was at a large parts store chain, a smooth chrome stock looking cap, never had any problems with pressure build up with it.

05-07-2004, 12:26 AM	#3
chevymad Registered User Join Date: Jan 2001 Location: skamokawa, WA, USA Posts: 527	The Napa "california" truck cap has a pressure relief at 3psi. They've got a check valve that lets air in no problem too. The regular caps have a one way check valve, lets air in but builds huge pressure like you're talkin about. I got tired of smellin gas in the cab when I had one. So much pressure would build the tank would actually start springing out. The california cap cured that.



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