IR tools (~Omegascope)will show different reading depending on the "emissivity" of the surface. They exhibit a not insubstantial temp reading difference from a polished steels to a anodised hardcoat Al or a flat witch-black mild St. The tool has to be calibrated to the surface finish. Alternatively, I would make a J or K type micro pill thermocouple and run it down the dip tube into the sump - or for "easy button" epoxy foil TC to the pan and run wire to the vehicle interior and install a fluke or becker via velcro(tm).
Exactly right! The dip stick is sort of shiny and has a bead of oil on it. I shoot for the oil drop. Close enough for gummint work....
