So the pop that I heard (it sounded like it came from the rear end so I didn't think it was cooling system related then again had no idea what it was as it caught me off guard) but when this happened it was 8pm and quite dark (also I was on a busy off ramp) but I didn't look under the car. The car was then towed back to my house. As far as me checking the coolant level, I did that this morning before I left for work so I didn't have much time to look around.
2000 323Ci with 129k. Nothing fancy but damn do I love the car.