Four Seasons 36990 Engine Cooling Fan Clutch

Four Seasons 36990 Heavy Duty Thermal Fan Clutch

The Four Seasons Fan Clutch 36990 is a heavy-duty thermal engine cooling fan clutch built with an aluminum body and reverse rotation operation. It is a new, non-electronic replacement that meets or exceeds OEM requirements and is performance rated for demanding cooling-system service.

Compatible With Ford F-150, F-250, F-350, Bronco, E-Series vans, Mustang, and select Dodge truck applications, this thermal fan clutch is built for reverse-rotation setups with a 4-bolt flange mount. The Four Seasons fan clutch line focuses on direct-fit cooling control for vehicles that rely on mechanical fan engagement.

Key Features

• Part number 36990 heavy duty thermal fan clutch
• Aluminum construction with raw aluminum finish
• Reverse rotation design for specific cooling fan applications
• 4-bolt flange mounting with 5/16-18 hole thread
• Non-electronic, thermal clutch type
• Meets or exceeds OEM specifications
• Performance rated for heavy-duty use
• New replacement part

Detailed Description

This Four Seasons Fan Clutch is engineered for vehicles that use a thermal, reverse-rotation mechanical fan system. The heavy-duty C-style clutch design helps regulate fan engagement based on temperature, supporting consistent engine cooling in trucks, vans, and performance-oriented Ford applications. With a 7.2-inch maximum diameter, 3.47-inch overall height, and flange-style mounting, the 36990 is built around the dimensional requirements listed for the application.

Use this part number 36990 when replacing a worn or inconsistent fan clutch on compatible Ford F-150, F-250, F-350, Bronco, E-150/E-250/E-350 Econoline models, Mustang, and select 1991 Dodge D150, D250, Ramcharger, W150, and W250 applications. This part cross-references Monroe Shocks & Struts (e.g., 272309) for the same application.

What It Helps Address

• Engine overheating caused by weak fan engagement
• Excessive fan noise from a failing thermal clutch
• Reduced cooling performance at idle or low speed
• Inconsistent fan operation in reverse-rotation systems
• Cooling-system wear from an aging mechanical clutch

Installation Notes and Tips

Verify reverse rotation, flange mount style, bolt circle, pilot dimensions, and overall height before installation. Mounting hardware is not included. Confirm the vehicle uses a thermal, non-electronic fan clutch and match the application notes for AC and heavy-duty options where listed. For Ford F-150, F-250, and F-350 applications, check the exact model year and cooling package before ordering.

Quality Assurance

Four Seasons 36990 is a new replacement fan clutch that meets or exceeds OEM requirements and is performance rated. The Four Seasons fan clutch line is built for direct-fit cooling-system service in confirmed applications.