Join Date: Aug 2018
Location: Fort Worth, Texas, USA
I use a meat temp probe. $15 at a big box store. It is fairly accurate between 140 and 240, the temps that interest me the most. Yeah, Chinese, dang it.
From your description, it sounds like your temp gauge sweep is too low. It needs to swing wider so that hot reads hot, not mid-range.
When I turn off the engine after getting it to full operating temperature, let it sit for a few minutes, then turn it back on, my temp gauge swings full right, "hot". Then it slowly drops to normal/mid-range, once I get coolant pumping through the block.
Build Date: July 18, 1966