Classic/Antique Car Repair: Radiator efficiency vs. engine temperature, oldsmobile delta 88, stock radiator

Question
1966 Oldsmobile Delta 88, 425 ci engine.  The stock radiator on this car is 3-rows.  The thermostat is rated 180°.  Does a 4-row radiator transfer "too much" heat from the coolant through the radiator, getting the coolant too cold for the normal engine operating temperature, thus causing the thermostat to have to open and close more often to maintain the correct engine temperature?  My Mechanic was warning me about using the 4-row because he said it would cause the thermostat to open and close too much.  I thought an efficient radiator would increase the amount of heat it can disburse to the air when there's extra demand for that, but not affect normal operation at cooler temperatures.

Answer
Hello Carl,

I suppose your mechanic's concerns are intuitively valid in a theoretically extreme case and could cause debate in a Thermodynamics class, but in actual use, the 4 row behaves exactly as you describe. It simply gives you more cooling capacity for heavy duty or performance conditions that place a heavier heat load on the system.  Hence, Old's made them standard on '88's with A/C and 442's, optional on all other models for a ridiculously low price if factory ordered. The extra cooling capacity simply provides reserve.

The thermostat is what controls the operating temperature until system capacity to cool is exceeded, then it remains open for maximum cooling, gradually closing only when normal 180 degree temperature is achieved.  As you know, it is actuated by a bi-metallic spring which simply doesn't react fast enough to cause the rapid cycling your mechanic fears.

Good luck with your car,

Bob