[R&B]

Question. Why would you want to connect your overflow line from your expansion tank to your radiator? Do I understand that correct and is that what you are doing? I also noticed a hole in the upper right hand corner of the radiator. At first I put a barbed fitting and then changed my mind and plugged it after I filled the radiator. My expansion cap is rated at 13 psi. If the cooling system builds up 13 psi of pressure, the cap should release the pressure. But if the radiator is at 13 psi and my over flow line goes to the radiator then I have a closed loop and essentially an enclosed system with no pressure release. Is my thinking incorrect and should I put the barbed fitting back in?