It seems like every time i drive at night the car will overheat and the oil pressure will go up at the same time the water temp goes up. i cut the heat on for about 5 seconds, and everything goes back down to normal. there is a new oil sending unit, so i know its not the gauge. the car has 225k miles and underdrive pulleys on the water pump and crank. my dad seems to think that the radiator may need to be reconditioned or replaced. all i know is that by spring im not going to want to cut the heat on wide open to make the water temp and oil pressure go down.