Gates K040378HD Serpentine Belt - Air Conditioning or Fan and Alternator

Heavy-Duty Micro-V Belt for Accessory Drives

The Gates FleetRunner Heavy Duty Micro-V Belt is built for demanding accessory drive service where durability and consistent belt tracking matter. Part number K040378HD uses EPDM construction with a polyester cord and a distinct green overcord to support longer service life on heavy-duty drives.

Compatible With Chevrolet Silverado, GMC Sierra, Cadillac Escalade, and other listed applications, this belt is sized for air conditioning and fan/alternator drive positions where stable operation is important. The K040378HD is an OE-improved replacement choice for fleet and work-truck maintenance.

Key Features

• Gates FleetRunner Heavy Duty Micro-V Belt line for demanding accessory drive systems
• EPDM belt material for durability, flexibility, and stability
• Polyester cord material for reinforced belt construction
• 4-rib K-section design
• Top width: 14 mm (.56 in.)
• Effective length: 962 mm (37.89 in.)
• Outside circumference: 978 mm (38.5 in.)
• OE Improved rating for replacement applications

Product Details

Gates engineered the FleetRunner Heavy Duty Micro-V Belt line to reduce downtime in fleet service by using a patented EPDM construction and a visible green overcord for added durability and flexibility. This K040378HD belt is a heavy-duty automotive V-ribbed belt with a K cross section and four ribs, making it a direct-fit option for accessory drive systems that need consistent tension and reliable pulley engagement. This part cross-references Dayco 5040378 and Continental 4K962 for the same application.

What It Helps Address

• Squealing or slipping accessory drive belts
• Cracking, glazing, or wear from age and heat
• Loss of belt stability on heavy-duty drives
• Poor A/C compressor or alternator belt performance
• Frequent belt replacement in fleet maintenance cycles

Installation Notes and Tips

Verify belt routing, rib count, and length before installation. Inspect pulleys, tensioners, and idlers for wear or misalignment, since those conditions can shorten belt life. Confirm the application by vehicle year, make, model, and position before ordering. Fits 1999-2008 Chevrolet Silverado 1500, Air Conditioning; Fits 2000-2008 GMC Yukon, Air Conditioning; Fits 2002-2008 Cadillac Escalade, Air Conditioning.

Quality Assurance

Gates FleetRunner Heavy Duty Micro-V belts are built with EPDM construction and an OE-improved design standard for heavy-duty service. Part number K040378HD is engineered for durability-focused replacement in listed Chevrolet, GMC, Cadillac, Hummer, Acura, and Honda applications.