Dayco 89949 Heavy Duty Automatic Belt Tensioner

The Dayco 89949 is a heavy-duty automatic serpentine belt tensioner engineered for demanding diesel engine accessory drive applications. Built to Dayco's No Slack® standards, this tensioner maintains consistent belt tension across varying engine speeds and loads, helping to protect drive system components and extend overall belt life.

Key Features:

• High-strength cast aluminum body resists cracking, fatigue, deformation, and contamination ingress
• Flat spring design reduces operating range vibrations and lowers the risk of bearing failure when a new belt is installed
• Highly damped construction using a wave spring and a metal ring with a bonded polymeric surface, acting as a radial shock absorber for the tensioner arm
• Lifetime lubricated bearings with double high-temperature seals for long-lasting, dependable performance
• Thermoplastic rubber spring slot plug keeps harmful contaminants out of the spring cavity
• Rubber O-ring seal guards against dust and grime intrusion
• Zinc-coated mounting hardware resists rust and corrosion
• Meets or exceeds OE quality standards

Designed specifically for heavy-duty diesel engine environments, the Dayco 89949 tensioner helps prevent belt slippage, reduces accessory drive noise, and supports longer service intervals. It is a direct-fit replacement that simplifies installation and restores proper belt drive system function.