Will my engine still run if the serpentine belt breaks?

No, if your serpentine belt breaks, your engine will likely not run for very long, if at all. The serpentine belt drives many essential components, including the alternator (which charges the battery), power steering pump, and water pump. While some engines might briefly run off battery power until it drains, lack of cooling (from the water pump) will quickly lead to overheating and engine damage.