Temp Too Low???

I'd rather see 180 year round. You should have enough radiator to hold 180 even in Seattle.

The thermostat controls engine temp if everything else is correct. If ambient is cool enough to hold temp to 140 but the Tstat is a 180 it shouldn't open until 180.


What I'm saying is if your cooling system is correct, it should run at Tstat temp or close to it year around regardless of ambient temp.

So I'd use a 180 Tstat and if it runs 190-195 in Seattle summer heat you'll be golden.