I think the confusion is due to defining what you want the tank to do.

Check this out: http://www.custompistols.com/cars/articles/overflow.htm

The use of an overflow tank (vented non-pressurized) is done for environmental reasons. It prevents a slightly overfilled radiator system from venting onto the ground.

The use of an expansion tank (pressurized), with a conventional radiator, adds a very small amount of additional coolant to the system.

Hope that helps! thumbs_up

John

Last edited by Hot Rod John; 07/02/2011 4:09 PM.
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