I ordered it last night! The 31x19. I've been NEEDING an aluminum radiator for quite sometime now. Last summer it reached 120 for 2 weeks straight. We were the hottest place on earth for 2 straight days! Is there any tips or special tools that I will need? How did everyone mix their water and antifreeze? I know it's 70/30. But how did you know how much to put in?