[Healeys] Changing the thermostat

[awgertoo at aol.com]

I need to change the thermostat in my wife's BN7--it is pretty cold here in 
 MD and the car warms up very slowly and ultimately will not get over  140 
degrees--undoubtedly it is stuck open.
 
I have a new 180 degree thermo and gasket.  Am I correct that all  I need 
to do is to drain the water level down to where it is below the level of  the 
thermostat, pull the old thermo and gasket and replace them with  the new 
180 degree one and the new gasket, bolt the thermo cover back on, refill  the 
radiator and run?
 
Best--Michael Oritt