Gas cap

[mbaker5479]

Quick question, I have a 71 c10 and the old gas cap was leaking when it was full and I would take a corner. Got a new locking gas cap and it seals great, now my cab smells like fuel, and when I open the gas cap it is releasing a large amount of fumes. The gas cap says it has the release on it for the vapors. Is this a bad gas cap or is there a plug in a check line? Any help is greatly appreciated.

Thanks
Mike

[54blackhornet]

71 could or could not require a vented cap ? Look behind passenger side of seat at the gas tank, if it has two hoses going into the top side of tank you have a closed evaporative system, it requires a Non Vented Cap. If these hoses are not present use a vented cap....

[MagmaJct]

I'm not certain, but a 71 may use a one way vented cap. One that allows makeup air to enter the tank, but vapors cannot escape. The vapors are then routed to a charcoal canister.

It's common for people to remove the charcoal canisters for various reasons, typically having nothing to do with functionality issues.

Typically removal causes more problems than it solves. Make sure your tank is vented to prevent it from collapsing, causing mysterious "vapor lock" symptoms, or bulging and over-pressure problems, including diluted motor oil.

Regards,
Mike

[leftybass209]

Welcome! It's time for you to slide your seat back and take a good look at your duel tank, it's associated hoses, and the fuel sender fittings.

[mbaker5479]

ok great, thanks a lot guys. I put the old cap back on and that fixed the issue (leaks fuel if filled up past 3/4, so definitely lets air in and out) but im pretty sure it doesnt have the canister in the engine bay. I will move the seat and check it all out.