dsi1 wrote:
> On Thursday, March 8, 2018 at 10:42:30 PM UTC-10, Steve W. wrote:
>>
>> Show me a car that has a sealed system that actually runs. They are all
>> vented through the charcoal canister. Water vapor can still get in as
>> well as the amount that is already absorbed into the ethanol in the gas.
>>
>> Dri-Gas can be helpful if you are using gas that has been stored a while
>> or that came from a store with low fuel sales. Or if you run straight
>> gas without ethanol like I do in all the small engines and vehicles when
>> possible.
>>
>> --
>> Steve W.
>
> There are valves in the fuel system to equalize tank pressure and the purge vapors from the charcoal canister. It's still a sealed system.

Air must enter the tank or it would collapse during fuel withdrawal.