expansion chamber

[kmhemi]

What does the expansion chamber do and do I need to keep it?

[ossiblue]

The expansion chamber is used in the non-vented fuel tank system to allow for the expansion of the gasoline vapors when ambient temperatures increase. Do you need it? To keep the fuel/venting system in factory specs, yes. If you remove it but keep the vapor system closed to the atmosphere--say by plugging the hoses to and from the tank--then you are doing no polluting to the atmosphere, but you run the possibility of problems when the vapors expand and have no place to go or when they contract and a vacuum forms which may interrupt adequate fuel flow from the tank.

There were several variations on the vapor/expansion system over the years so without knowing the year of your car, how critical the tank is to the functioning of your car is just a general statement. Many car owners removed them for some reason and the cars run fine, and some do pollute. It is a silent, harmless, non-mechanical piece of equipment that does serve a purpose so removing it might cause more trouble than it's worth.

Do a search and find the threads on the vapor recovery system and you'll see diagrams of the different set ups and comments/opinions on removing the various components

[kmhemi]

I'll keep it.
Thanks for the help.
Keith

[RWebb]

some idiot removed mine and I can't fill up the tank w/o having 1 qt. or more of gas splash all over the apron at the gas station

if anybody has a spare for an early car, let me know...

[911s55]

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