Thanks, L1ftmech. When I changed the oil last week and started the engine, the upper rad hose was warming up within five minutes, well before engine operating temperature was reached. I know that, in engines with the stat located at the upper rad hose, this indicates a thermostat not closing properly. But this engine has the stat located on the lower rad hose. I have a IR temp gun and will investigate temperatures to see if the engine is reaching full operating temperature. I will probably replace the stat anyway.

The dipstick falsely indicating water does not apply in my case since the engine oil really had a lot of emulsified water in it when it was drained.

As per your suggestion, I will focus on the operating temperature.