2.3 DOHC motor - correct operating temp

[fixkick]

now lets look at heat.  (engine to coolant)
see this great drawing graph...
in closed loop , the black vertical line is at stoich,
then if fuel goes lean to the right a bit, efficiency  rises , heat the the water jackets goes DOWN as the red line peaks,.
The reason we use Stoich is for low smog, not max HP see on gray cloud point.
Unless you go super lean (and felt in the seat of the pants) it will not run hotter coolant.
yes lean can burn exhaust valves tips. as the do get hotter, but not the water jackets. (this lean hot combustion lasts for shorter time, and does not expose the cylinder walls with more heat but less (yes complex that) that is why late timing puts  too much flame front on the walls, of the cylinder. bad for the cooling system that.

The leaning out, same fuel used (volume) makes more HP, and wastes less heat, until the cold air (oxygen) is so great the fuel is heating mostly air, and efficiency drops.
so lean only wastes heat if way too lean. waste heat is the inverse of the red line here.
not to mention once too lean the spark can not fire off the lean mix and it misfires.




I bet you , your engine is not overheating the coolant.  in fact a tad lean is less heat to the coolant.
misfire can be a cold slug of air.
or way too late to spark fire and then dumps lots of heat the the cylinder walls. just like late timing does. (and HP FALLS off FAST) felt..