The Thermostat Housing Functions

[Dynomite]

Some Thoughts regarding the Thermostat Housing:
1. It does not make any difference if you use a 160 deg thermostat or 180 deg thermostat....they both are fully open at 185 deg.
2. I makes no difference if you drill small 1/8" holes in the thermostat flange as the additional flow area (.0123 square inches) is only 1.5% increase per hole over the Thermostat Full Open area of .785 square inches.
3. The Heater Circuit is open at all times even on a cool engine after start as the heater will be the first to get warm coolant.
4. On a very cold day with the heater on and Interior Fans set at Ten, the Heater Core with significant coolant flow could cool the engine for a significant amount of time before the main temperature controlled end of the Thermostat on the radiator side opens. The engine coolant mixed with some air would still expand into the radiator and to the coolant over flow below the passenger headlight.
5. If you want to cool your engine below the temperature controlled thermostat on a cold day or cool your engine a bit more on a very hot day, run your Heater with Interior Fans set at Ten using Outside Air (not recirculate) with windows open. The additional Coolant Flow through the Heater could be as high as 14% of the total coolant flow with 3/8 inch ID Heater Hoses.
6. The bottom of the thermostat on engine side opens at differential pressure of 5psi when open 1/2 inch allowing coolant to bypass the radiator (Marc Haibeck Testing).
7. When the thermostat has not reached opening temperature (175 deg) the coolant recirculates through the bottom of the thermostat at a pressure of 5psi since the coolant flow through the radiator is blocked.
8. Always use original green coolant GM 1825M.

Heater Hose Connection on Thermostat Housing

See Item #2 Replacing the Heater Core and Heater Hose Connection




See Item #8 The 180 deg versus the 160 deg thermostat or no thermostat