Serpentine Belt Routing
The specific path a serpentine belt must follow around the various engine pulleys and tensioners.
Serpentine belt routing refers to the specific, complex path that a single serpentine drive belt must follow around the various engine pulleys and tensioners. The belt must wrap around the crankshaft pulley, alternator, power steering pump, A/C compressor, water pump, and idler pulleys, ensuring that each component spins in the correct direction and has sufficient belt contact to prevent slipping.
Because the belt must weave between multiple accessories, routing is highly specific to the vehicle's engine design. Most vehicles feature a routing diagram decal located under the hood, on the radiator support, or in the owner's manual. Without this diagram, installing a new belt can be challenging due to the numerous routing possibilities.
Routing the belt incorrectly can cause major issues: accessories may spin backwards (like the water pump, causing engine overheating), the belt may rub against the engine block, or the tensioner pulley may not be able to apply proper tension, leading to the belt slipping off or snapping. Technicians check the routing carefully during belt replacement.