Well i drive a 2001 Acura EL and just finished dropping in a k24a1 motor in it . A brand new motor with less then 5 km on it. It has been the second night that we start the car and the temperature for the coolant goes up to 237 digress when i drive not even a 1/4 mile down the road. But if i am in the garage and reeving it a 3000 rpm for about 5 min the temperature is 197 to 200 digress. So we change the coolant sensor and it did the same thing.We put a brand new head gasket and the head was machined also. Would it be possible that the head bolts became loose ?? or it is the head that is the problem . Looking for you guy's suggestion of what is the problem ??