Regarding the thermostat valve issue...
Normally , there are connections for car AC heater, hot water from the engine passes thru the heating coil and goes back to the pipe connected to water pump.
In my case the heating system is disconnected and instead of pipes there are stopper installed , one near the thermo valve and other down near the starter motor.
If I install thermostat valve and when it is closed (engine temp is below optimal range) it will neither allow hot water to flow thru radiator nor will it be able to pass thru the heaters coil which it normally does even if the valve is closed or open.
So the question is do i have to reconnect heating coil in case i install the thermostat valve or will it work without the connections to the heater.