I would use a scanner to read the actual coolant temperature, it’s read by the ECT sensor near the thermostat. The computer uses this value. The cluster gauge uses the sender on the side of the block, and I’d be hesitant to rely on it for much of anything. On my two 98 models, it normally reads at the major tick mark halfway between 100 and 210 while the ECT reports 190.
If you don’t have a scanner, you can use a Bluetooth OBD adapter and download the DashCommand or CarGaugePro apps, among others. Those two have the advantage of being able to read the CMP retard on the distributor.
The sensor should be reading near the thermostat setpoint, 190-ish. Seems to me that the lower hose should be colder than the upper since that this the radiator outlet. Maybe others can confirm just how much of a temperature difference it should be.
Sent from my iPhone using Tapatalk