So I have to ask, how many people on here are running after aluminum radiators? I recently bought an all Aluminum Yonaka Honda Half Size Radiator. It was a very good deal, 150 bucks for a beautiful well put together rad that comes with a metal fan shroud and a new cooling fan. Being a dual core radiator; I kept the same cooling capacity as my OEM radiator. Well basically I have had nothing but problems with my cooling system since I got it. Car is fine at idle. Unfortunately on hot days while traveling uphill like in the mountains the cars temp gauge starts climbing. And every time I use the AC it over heats as well. I have to leave the blend door on heat and bringing in outside air. I am assuming I am not getting enough airflow since the car is fine at idle. I am running an 80 to 20 percent mix of distilled water to Toyota OEM Red Coolant. Also running a 170 degree thermostat as opposed to the OEM 185. Sorry for the long post but just tired of spending money and the problem not getting fixed.