Well I did something thing(s) stupid.
I remember what a friend said when we were kids: "everything you do takes 5 minutes or 5 hours, no exception". The temperature sensor was bad on an engine and when I replaced it that last little tweak snapped it off. Thankfully a screw extractor got it out. I ordered one shipped overnight and in a hurry to install dropped it...but where? After taking radiator, fan, pulleys, etc. off I spotted it inside harmonic balancer, last place I looked. Small forceps got it out.
Installed it works fine.
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