#1
As long as there is some anti freeze in the system
it will keep it from corroding on the inside
If left empty or even capped off there is nothing to protect it from corrosion.notice that any radiator that is left outdoors will turn green on the inside(and outside),thats oxides of copper.
I guess in the summer time, you can restrict the flow to the heater core, just as long as there is some anti freeze running thru the system.
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