So I was out last night and around 10 pm or so when I turned on my car which was parked on this steep hill my low coolant light came on. I got scared that my car was going to blow up or something so I went home immediately. There was no steam. The gauge for the heat of the car was like halfway between cold and hot but it was also like 90+ degrees outside as well. I got my fluids changed for the car on Wednesday so I don't know why I would have low coolant already. I look at the receipt and it says "36 below 0" on the radiator. Does this mean it needs fluids or what? Is 0 where it needs to be and it's 36 below that? I don't understand what that means. Can anyone help me? Sorry I don't know anything about cars.