Four Seasons 86148 Engine Coolant Thermostat Housing

Thermostat Housing for Audi Cooling Systems

Four Seasons 86148 is an integrated engine coolant thermostat housing built from plastic and supplied with the thermostat and gasket or seal included. It meets or exceeds OEM requirements and is made for direct replacement in select Audi cooling system applications, including Audi A4, A4 Quattro, A5, A5 Quattro, A6, A6 Quattro, and Q5 models.

The Four Seasons Thermostat Housing line focuses on engine coolant components that restore proper coolant flow control and sealing at the thermostat assembly. Part number 86148 is an OE-style integrated thermostat housing for vehicles that use a thermostat-in-housing design, helping simplify service on the cooling system.

Key Features

• Integrated thermostat housing design with thermostat included
• Gasket or seal included for the housing interface
• Plastic construction for OE-style fit and function
• Meets or exceeds OEM specifications
• Inlet port diameter: 1.005 in.
• Bolt hole center to bolt hole center: 2.15 in.
• Flange thickness: 0.5625 in.
• Overall height: 4.181 in.

Detailed Description

Four Seasons 86148 is an integrated thermostat housing designed for engine coolant systems that use a combined thermostat and housing assembly. This part number 86148 is a direct-fit replacement for select Audi cooling system applications and is listed for 2005-2009 Audi A4, 2005-2009 Audi A4 Quattro, 2008-2010 Audi A5, 2008-2010 Audi A5 Quattro, 2006-2011 Audi A6, 2005-2009 Audi A6 Quattro, and 2009-2012 Audi Q5. It is also cross-referenced to Continental 49479 for the same application.

Use this thermostat housing when servicing a leaking, warped, or worn coolant outlet assembly on Audi A4, Audi A6, or Audi Q5 cooling systems. The integrated design supports a clean replacement of the thermostat housing assembly while maintaining the correct sealing surface and coolant passage dimensions.

What It Helps Fix

• Coolant leaks at the thermostat housing or seal surface
• Cracked or warped plastic housing from heat cycling
• Improper thermostat operation caused by a worn integrated assembly
• Cooling system temperature control issues related to housing failure
• Service problems on Audi coolant outlet assemblies with integrated thermostats

Installation Notes and Tips

Verify engine code and cooling system configuration before ordering, since the same model may use different thermostat housing designs. Inspect the mating surface, coolant hoses, and adjacent plastic fittings during installation, and replace contaminated coolant after service. Confirm the inlet port diameter, bolt spacing, and overall housing style match the original part before installation.

Quality Assurance

Four Seasons 86148 is manufactured to meet or exceed OEM specifications for the listed applications. The part is built as an OE-style replacement for Audi cooling system service and is intended to match the original integrated thermostat housing design.