Just replaced the leaking radiator in my Forester. How important is the foam strip that is taped along the top? The A/C one is still in there. I assume this keeps air flowing through radiator and blocks air flow from coming over the radiator.

Yeah the foam strip purpose is to force air thru the radiator, not over top of it. witout it, the easy path for air is over top, so makes cooling system work harder than it needs.

 

I have replaced the foam on a few with simple flexible plastic strips, cardboard, shingles, etc. You can be as creative as you want, but you should put something in there as opposed to going without.

Cool. I can probably reuse the one from the old radiator once I find some double sided tape to put it back on with.