[rqjoe]

I used to think a little cooler was OK. But don't any more. Engine was designed to run at a certain temp (with a 'range' of okayness.) The code is telling you it is outside what is expected from OEM design. I would be concerned if the cooling system (t-stat, radiator, pump, coolant passages, hoses, etc.) wasn't functioning properly, but I would not put in a cooler t-stat just to run cooler. You are probably "OK" with a cooler t-stat but engine is not running at optimal design state. Cooler engine will affect all sorts of things: emmissions, sealing of gaskets, power,.....)