Quote Originally Posted by moondoggie
Good Day!

"Why would flow only increase 9% through the radiator? Hmm, the outlet of the dual stat system didn't increase in size did it? Exactly." Which makes me wonder all the more - why the dual 'stats?

Blessings!
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The thermostat has a flow area considerably less, and restriction considerably more, than the outlet, hose, and radiator core. Duals closes the gap between them, and also allows more of a progressive and responsive engagement. Redundancy would be a bonus, but not by design.