You will know you have a bad oil pan by noticing oil that has physically leaked onto the ground. With oil pan problems, you will usually not get the smell of burning oil or see any oil contact with the motor. The pan is designed to keep the large quantity of oil stored there away from your engine block. Oil pans will often get dented. There is usually no cause for alarm as the oil pan is sturdy enough to handle it. You would only need to act if you noticed it has been jarred loose, has an oily seal meaning there is a possible leak coming, or actually see oil leaking from a puncture or something similar.