Dayco 5120903 Heavy Duty 12-Rib Serpentine Belt – 12PK2290

The Dayco 5120903 is a heavy-duty 12-rib Poly-V serpentine belt designed for demanding commercial truck and diesel engine applications. Built with EPDM material and aramid-reinforced cords, this belt is engineered to handle high torque, power pulses, heat, and the demanding accessory drives found on heavy-duty vehicles.

The 5120903 features a 90.25-inch effective length, 90.88-inch outside circumference, and 1.66-inch top width. It is commonly used to drive accessories such as alternators, water pumps, fan drives, A/C compressors, and power steering pumps, depending on the vehicle application.

Key Features

• Genuine Dayco heavy-duty Poly-V serpentine belt
• Dayco Part Number: 5120903
• 12-rib design
• Industry size: 12PK2290
• Effective length: 90.25 inches
• Outside circumference: 90.88 inches
• Top width: 1.66 inches
• EPDM belt material
• Aramid-reinforced construction
• Designed for heavy-duty diesel applications
• Heat and wear resistant
• Suitable for demanding multi-accessory drive systems

Common Cross-Reference Numbers

• Cummins 3100189
• Cummins 3103836
• Cummins 3682285
• Cummins 3682893
• Caterpillar 281-2055
• Navistar 3565410-C1
• Navistar 3829896C1
• Gates K120901
• Gates K120903
• NAPA 25-120903
• ACDelco 12K901 / 12K903
• Goodyear 1120903 / 4120902 / 4120904
• Continental 4120902 / 4120904

Important Fitment Information

Always verify the belt routing, rib count, effective length, and application before ordering. Belt fitment can vary based on engine, accessory configuration, and vehicle specifications.

Brand: Dayco
Part Number: 5120903
Belt Type: Heavy Duty Serpentine / Poly-V
Rib Count: 12
Industry Number: 12PK2290
Effective Length: 90.25 in.
Outside Length: 90.88 in.
Top Width: 1.66 in.
Material: EPDM
Reinforcement: Aramid
Color: Black
Condition: New