Taking Bobcowan’s suggestion, I tried the infa red thermometer and yes, my
oil pan temp is 175+/- degrees so either my gauge or sender is bad. My sender is mounted on top of remote mounted
oil filter. In removing it, it appears to be perhaps too short to protrude directly into
oil flow. Also, reading Stewart Warner gauge installation info, the say not to use sealer tape in mounting sender because the contact with motor is the ground. My sender is mounted into a threaded reducer fitting, allowing the smaller diameter sender to fit into the larger diameter opening in filter bracket. The reducer fitting appears to have had some tape in the threads. Perhaps that’s the problem.