Dayco 5100678 Serpentine Belt

Dayco 5100678 Serpentine Belt Overview

The Dayco 5100678 serpentine belt is a K-section accessory drive belt built for demanding engine accessory systems. It uses EPDM construction with aramid reinforcement for stable performance across a wide temperature range and consistent rib engagement.

Compatible With Volvo and Mack applications that call for a 10-rib K-section belt, this belt is sized at 67.75 inches effective length and 68.38 inches outside circumference. The Dayco 5100678 is also cross-referenced in common heavy-duty belt catalogs for the same application.

Key Features

• EPDM rubber construction with aramid reinforcement
• 10-rib, straight-rib K-section profile
• Top width: 1.38 in.
• Effective length: 67.75 in. (1720.85 mm)
• Outside circumference: 68.38 in. (1736.86 mm)
• Operating temperature range: -45°F to 212°F
• Built to SAE J1459 and SAE J2432 standards

Detailed Description

Dayco 5100678 is a black serpentine belt for accessory drive systems that require a 10-rib K-section design. The EPDM compound is paired with aramid reinforcement to support belt stability under heat, cold, and continuous engine loading. This makes it a practical replacement choice for heavy-duty truck and commercial vehicle belt drives, including Volvo and Mack applications where the specified dimensions match.

This part cross-references Gates K100677 for the same application. When replacing a worn belt, verify rib count, section type, and measured length against the original belt or service information before installation.

What It Helps Address

• Squealing or chirping from a worn accessory drive belt
• Cracking, glazing, or rib wear on the existing belt
• Loss of proper drive to alternator, water pump, or other belt-driven accessories
• Belt tracking issues caused by incorrect width, rib count, or length
• Service replacement for heavy-duty Volvo and Mack belt applications

Installation Notes and Tips

Confirm the belt path, pulley alignment, rib count, and effective length before installation. Inspect tensioners and idlers for wear, since damaged components can shorten belt life. For best results, compare the removed belt to the Dayco 5100678 and verify the K-section profile matches the original application.

Quality Assurance

This serpentine belt is manufactured to SAE J1459 and SAE J2432 standards for accessory drive belt applications. Its EPDM and aramid-reinforced construction is specified for durability across a broad operating temperature range.