I recently purchased a heating element for my son's Magic Chef oven because the previous element broke in two. He had not had problems prior to that element breaking. With the replaced element, when he sets his oven to preheat to 350 it heats to over 600 degrees. It seems resasonable to assume that the previous element overheated the last time it worked and that's what caused it to break.....but I'm obviously not an appliance repair person! Can you tell me what the cause would be of the oven overheating so that we can look into replacing what has gone bad? We do not know the exact age of this oven. Thank you for any direction you can give.