Don’t you hate it when you hear that squeal from under the hood when you’re driving aroun Denver? It usually means there is a problem with the serpentine belt. The serpentine belt powers a lot of engine accessories. It runs the alternator-which charges the battery, the water pump-which cools the engine, the air conditioning and the power steering pump. All pretty important parts. It is called a serpentine belt because it snakes around a bunch of engine components.