In one word, NoX. The higher your engine temperature the more NoX produced. The green house gas is produced when the combustion chamber temperature exceeds 1500 degrees (might be 2500) 25 to 40 degrees F over proper engine temperature will more than likely produce a large amount of NoX gas.

Had a friend that had low flow through the radiator yet it was undetectable on the temperature gauge! Up a steep road could have tipped him off to the problem but not on the flats in Ca. in the winter. Measured aprrox 2100 NoX before radiator was rodded than 500 NoX after...WOW!!!


My .02 fwiw