Going back to Romans 1st post when you refil the car with water for the first time you need to also fill the entire engine block and head up to the bleed screw before you ever start the engine. If not then while you are running the enging to heat it up up and open the thermostat you are dry cookong your engine, the radiator is full and the expansion tank is full , trhe engine/ head is dry inside. Seeing steam means no water or air bubble Not good.

 

Is changing out the thermostat and switch for a lower temp unit really common?

I ask because engines are most efficient and perform the best at around 180*F/82*C and engine components are at their proper expansion at that temp. Running a lower temp thermostat reduces the efficiency of the engine and will cause wear quicker to internal parts.

Using distilled water is the proper way to mix coolant.

 

AScholtes, if your engine runs below 82*C, you will lose on the gas mileage that I know. Changing out the Tstat and thermalswitch is common because these parts fail after time and owners get worried about overheating the engine and warping the head. For early cars there are at least 3 Tstat options:
71*C, 82*C and 92*C. For thermal switches (Wahler) there are 4 options: 65/60*C, 75/70*C, 82/77*C and 92/87*C. Bearing this in mind you should be able to set up your cooling system to follow operating parameters.

 

Spanky - thanks for the warning

I'm keeping the low-temp stuff in the car

my issue now is that it seems that every day I have to add a little water/antifreeze, there are no leaks that I can see, and my oil level is fine ... engine working harder then it should?

 

If you can get your hands on a cooling system pressure tester, this will help you find your leak. Remove your spark plugs, top off the system with water/ antifreeze and then hydro static test it to 20 psi and see if the pressure drops at all over the next 10/15 mins. If the system is tight it will maintain 20 psi for 20/30 min easy. Use a fleshlight to look down into each cylinder to see if you can spot any sign of water leaking in. Car should be cold for this test. You may have a very small head gasket leak. You can also have a hydro carbon gas test conducted on a collected sample of your antifreeze/ water by your local well equiped repair shop. This will point blank finger of rule out the head gasket as a problem. Good luck.