Weird Temperature Issue

[timjamz]

Howdy, all! I'm a new Yaris owner but long-time Corolla, Camry, 4-Runner, Sequoia owner and DIY repair person.

My scenario: Just bought a 2007 base sedan, manual transmission. The temperature "cool" light comes on at cold start and goes off after a few minutes, as expected (I wish it had a normal gauge, but I digress). After driving for 20-30 minutes no "overheat" indicator (ambient outside temp around 70F). Seems to operate just fine. I have replaced the red coolant and thermostat with jiggle valve at 12-o'clock (along with oil, gear oil, brake flush, etc being a new purchase).

My question: Is it normal on this vehicle (1NZ-FE) for the lower radiator hose to remain cool to the touch and the front fan to never come on? The upper hose gets plenty warm, but not like scorching hot. Cabin heat gets normal hot. Squeezing upper and lower hoses sloshes the coolant around like normal (not hard as if there was a blockage). When re-filling coolant, plenty of air gets burped out like a normal drain & fill. I've ordered an Aisin water pump, thinking surely it must be on the way out, since the lower hose is cool and no fan triggered... is that a good guess, or does this motor just run super cool?

Thanks for any tips and feedback!