Dayco 5080900 Serpentine Belt - Fan, Alternator and Idler or Main Drive

Brand Dayco 5080900
Position Fan, Alternator and Idler and Main Drive
Material Epdm, aramid reinforced
Top Width 1.10
Color Black
Effective Length 2286.00
Effective Length 90.00
Outside Circumference 2302.01
Outside Circumference 90.63
Rib Quantity 8
Cross Section K-section
Maximum Operating Temperature 100
Maximum Operating Temperature 212
Minimum Operating Temperature -42.7
Minimum Operating Temperature -45
Rib Depth Standard
Rib Profile Straight rib
Standards Sae j1459, sae j2432
Fits Ford and Mercury · 9 vehicles

Aramid reinforced. EPDM construction adds strength and durability for dependable belt performance.

Straight rib profile. Helps maintain consistent contact and smooth power transfer.

SAE J1459, SAE J2432. Built to meet recognized belt performance standards.

Cross-references Cummins 3978279, Driveworks 900K8 and Duralast 900K8 for the same application. See all 30.

$43.92Free shipping
In stock · usually ships same day before 1pm CST
Step 1 — Confirm fitment
Free return shipping if it doesn't fit when you check fitment here first.

Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
Step 2 — Quantity
Order total $43.92
Free shipping to the continental U.S.
Free returns within 60 days if it doesn't fit when fitment is verified.

Dayco 5080900 Serpentine Belt Overview

The Dayco 5080900 serpentine belt is a K-section accessory drive belt built for main drive applications that demand stable grip and consistent power transfer. It uses EPDM with aramid reinforcement for durability, with an 8-rib straight-rib profile and a black finish.

Compatible With 1989-1995 Ford Thunderbird, Main Drive, and 1989-1990 Mercury Cougar, Main Drive. This Dayco 5080900 belt is also cross-referenced to Motorcraft JK8-904 for the same application.

Key Features

  • EPDM construction with aramid reinforcement for strength and wear resistance
  • 8-rib K-section design for accessory drive applications
  • 1.10 in. top width for proper belt tracking
  • 90.00 in. effective length and 90.63 in. outside circumference
  • Straight rib profile with standard rib depth
  • Operates from -45°F to 212°F
  • Built to SAE J1459 and SAE J2432 standards

Detailed Description

Dayco 5080900 is a serpentine belt for the main drive system on select Ford and Mercury vehicles. It is specified for 1989-1995 Ford Thunderbird and 1989-1990 Mercury Cougar applications, where the accessory drive belt must maintain consistent engagement across multiple pulleys. The EPDM rubber compound and aramid reinforcement support long-term belt stability under heat, cold, and continuous engine operation.

With its 8-rib K-section profile, this belt is sized for accessory drive routing that depends on accurate rib alignment and dependable tension retention. The Dayco 5080900 is a direct-fit replacement option for owners servicing a Ford Thunderbird or Mercury Cougar main drive belt system and looking for a part that matches the listed dimensions and standards.

What This Belt Helps Address

  • Squealing or slipping from a worn serpentine belt
  • Cracking, glazing, or rib wear on the accessory drive belt
  • Loss of accessory drive performance from belt stretch or age
  • Improper belt tracking caused by incorrect belt dimensions
  • Service replacement for aging Ford Thunderbird and Mercury Cougar main drive systems

Installation Notes and Tips

Verify belt routing, rib count, and length against the existing belt before installation. Inspect pulleys, tensioners, and idlers for wear or misalignment, since those conditions can shorten belt life and affect tracking. Confirm the application is the main drive position on the listed vehicle before ordering.

Quality Assurance

This Dayco serpentine belt is manufactured to SAE J1459 and SAE J2432 standards and uses EPDM with aramid reinforcement for consistent performance in demanding accessory drive service.

This part fits 9 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelLitersCylindersPositionNotes
1995FordThunderbird3.8LV6Main Drive
1994FordThunderbird3.8LV6Main Drive
1993FordThunderbird3.8LV6Main Drive
1992FordThunderbird3.8LV6Main Drive
1991FordThunderbird3.8LV6Main Drive
1990FordThunderbird3.8LV6Main Drive
1990MercuryCougar3.8LV6Main Drive
1989FordThunderbird3.8LV6Main Drive
1989MercuryCougar3.8LV6Main Drive
Directly replaces or cross-references 30 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
Cummins — 3978279Driveworks — 900K8Duralast — 900K8Dynacraft — 4080902DYCDynacraft — D84-1000-1082285Dynacraft — D1108-0015Dynacraft — D1108-0063Dynacraft — D1108-4840Dynacraft — D1108-4861Dynacraft — D1108-7647Ford — E9SE-8620-HBFord — E9SE-8620-HCFord — E9SZ-8620-JFord — EDSE-8620-HBFord — EDSE-8620-HCFord — F4SE-8620-GAFreightliner — 01-23415-063John Deere — H174455John Deere — R131433John Deere — R133402John Deere — R500381John Deere — R524012John Deere — R1314333John Deere — T356326John Deere — T360494Mack — 5264521Mighty Distributing System — 8K897Motorcraft — JK8-904Navistar — 89763-K8V&W — 900K8