DAY5120477

Includes (sold as a single belt):

• 1× heavy‑duty 12‑rib serpentine/fan belt for Paccar MX‑13 front‑end accessory or fan drive systems.​
• Gold Label construction optimized for tight idler layouts and high belt tension around multiple fan and accessory pulleys.​
• Designed to work with OE tensioners and pulleys on MX‑13 fan drives, converting crankshaft power into airflow and accessory output.

Dayco 5120477 is a 12‑rib heavy‑duty Poly Rib serpentine belt engineered for Paccar MX‑13 fan and accessory drives in Peterbilt and Kenworth applications, where compact pulley spacing and high loads demand superior grip and durability. 

Fits Heavy‑Duty Trucks with Paccar MX‑13

• Peterbilt 365 with MX‑13 (fan belt / 12PK1212).​

• Kenworth T680 12.9L MX‑13 (fan multi‑rib belt, 2015–2022).​

• Other Peterbilt and Kenworth models using MX‑13 engines and 12‑rib 47.7" fan belts; verify by 12PK1212 spec..