When it was cooler I would cruise at about 188 and could even see the thermostat cycle some and that was with the 190* stat, but now it's just freaking hot. I have noticed that if I turn off the AC that the temp will come down, so that tells me I am at the ragged edge for this radiator. I thing when the radiator was replaced by the previous owner they just went with a 5/8" core and called it good.