Dayco 5120646 | Serpentine Belt

Part Number
Serpentine Belt

Fits: 11-14 Kenworth T660, 11-13 Kenworth T700, 11-13 Kenworth T800, 11-13 Peterbilt 365, 11-14 Peterbilt 367, 11-14 Peterbilt 384, 11-13 Peterbilt 386, 11-13 Peterbilt 587, 12-13 Peterbilt 389, 13 Peterbilt 579

Special Price $40.79 Regular Price $47.99
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Estimated Ship Date: 1 Business Day or Less
The Dayco® Poly Rib® Belt is designed for power transmission on heavy duty multiple-accessory drives. This Poly Rib belt is the latest version of the revolutionary multi-ribbed belt first developed by Dayco® for the 1979 Ford® Mustang®. The Dayco® Poly Rib® Belt is manufactured from an extreme temperature EPDM rubber and features a construction that uses a highly fiber loaded compound to maximize belt life and load carrying requirements while minimizing pulley misalignment noise. This belt offers excellent resistance to high under hood temperatures and ozone contamination. In addition, specially formulated treated cord insures length and tension stability on heavy duty diesel engine drives for the life of the belt. The Dayco® Poly Rib® Belt meets or exceeds SAE J1459 and SAE J2432 specifications.

BRAND: Dayco




Cross SectionK-Section
Effective Length64.57
Effective Length1640.08
MaterialEPDM, Aramid Reinforced
Maximum Operating Temperature100
Maximum Operating Temperature212
Minimum Operating Temperature-45
Minimum Operating Temperature-42.7
Outside Circumference1654.31
Outside Circumference65.13
Rib DepthStandard
Rib ProfileStraight Rib
StandardsSAE J1459, SAE J2432
Top Width1.66

64 1/2 In. Belt



  • CARQUEST: K120645HD
  • Gates: K120645HD
  • ACDelco: K120645HD
  • NAPA: 25-120645HD


  • 2011-2014 Kenworth T660 - Position: Fan
  • 2011-2013 Peterbilt 386 - Position: Fan
  • 2013-2013 Peterbilt 579 - Position: Fan
  • 2011-2014 Peterbilt 367 - Position: Fan
  • 2013-2013 Peterbilt 389 - Position: Fan
  • 2011-2013 Kenworth T800 - Position: Fan
  • 2012-2013 Peterbilt 587 - Position: Fan
  • 2011-2013 Peterbilt 365 - Position: Fan
  • 2011-2014 Peterbilt 384 - Position: Fan
  • 2011-2013 Kenworth T700 - Position: Fan
Customer Questions
Can a serpentine belt cause smoke?
Yes, a serpentine belt can cause smoke. A serpentine belt is an essential component of a vehicle's engine system. It drives various accessories such as the alternator, power steering pump, water pump, and air conditioning compressor. If the serpentine belt becomes worn, damaged, or misaligned, it can cause friction and generate smoke.
Why is my serpentine belt squealing?
The serpentine belt can squeal due to various reasons, including tension issues, worn-out belt, or a problem with the belt's pulleys.
Is my serpentine belt too tight?
If your serpentine belt is causing issues like excessive noise or accelerated wear on the pulleys, it may indicate that the belt is too tight.
Why did my serpentine belt come off?
Serpentine belts can come off due to factors such as belt wear, improper tension, misaligned pulleys, or a faulty tensioner.
Please, mind that only logged in users can submit questions

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