Four Seasons 85139A Engine Coolant Thermostat Housing

Thermostat Housing for Ford and Mazda Applications

Four Seasons 85139A is an engine coolant thermostat housing built for direct replacement use in select Ford, Mercury, and Mazda applications. It uses thermoplastic construction, includes the gasket or seal, and is supplied without a thermostat for service jobs that require the housing only.

Compatible With 2001-2010 Ford Explorer, 2001-2003 Ford Explorer Sport, 2001-2005 Ford Explorer Sport Trac, 2002-2011 Ford Ranger, 2006-2010 Ford Mustang, 2001-2010 Mercury Mountaineer, and 2002-2008 Mazda B4000. Four Seasons 85139A is also a direct interchange for several OE-style replacement numbers used in the same cooling system applications.

Key Features

• Engine coolant thermostat housing for cooling system service
• Thermoplastic material for OE-style replacement fitment
• Gasket or seal included
• Thermostat not included
• Meets or exceeds OEM requirements
• Style: without thermostat
• Part number: 85139A

Product Details

The Four Seasons Thermostat Housing line focuses on engine coolant components that restore proper sealing and coolant routing at the thermostat mounting point. This housing is specified as a thermostat housing type, with a non-symmetrical base and no thermostat included, making it a practical choice when replacing a cracked, warped, or leaking housing while reusing the thermostat if it remains serviceable. Four Seasons 85139A is a fitment-based replacement for Ford Ranger, Ford Explorer, Ford Explorer Sport Trac, Ford Mustang, Mercury Mountaineer, and Mazda B4000 cooling system service.

This part cross-references Monroe Shocks & Struts 902060 and Motorad CH5139 for the same application.

Common Repair Uses

• Coolant seepage at the thermostat housing
• Cracked or heat-damaged plastic housing
• Warped sealing surface causing coolant loss
• Thermostat housing replacement during cooling system repair
• Restoration of proper coolant flow path after housing failure

Installation Notes and Quality Assurance

Verify engine-specific fitment before installation, since these vehicles can use different cooling system configurations. Inspect the mating surface, replace worn seals as needed, and confirm the thermostat condition before reassembly because the thermostat is not included. Four Seasons 85139A is built to meet or exceed OEM requirements for the listed applications.