Thermostat rating / actual operating temp

[Bill Roosa]

also make sure the overflow tank still has the tube that sticks down to the bottom of the tank

 

[Skipper]

also make sure the overflow tank still has the tube that sticks down to the bottom of the tank

My expansion tank is a Sendure aluminum. (Pic)
There is no overflow tank. If I overfill it, when running it spits the excess through the hose under the cap into an area of the hull between the engine stringers, auto-leveling the coolant amount that it wants in the expansion tank. This is the original setup.