I like the fan. But months ago, I removed both temp sensors and cleaned any tiny bit of scale away. And I swapped out the two wire one that the ECU reads.

I guess the difference between radiator and ECU could also be a combination of accuaracy of IR themometer, accuracy of ECM coolant temp sensor, air bubble enclosing coolant sensor, scale, and copper radiator radiates heat better than thick aluminum castings.

What I get from this is that I better get Santa to bring me that Ultra Gauge.

In the 97 the two temp sensor are side by side.

 

Did you replace the dash temp sensor too?