Four Seasons 86258 Engine Coolant Thermostat Housing

Thermostat Housing for BMW Cooling Repair

Four Seasons 86258 is an integrated engine coolant thermostat housing built from plastic and supplied with the thermostat already included. It is made to meet or exceed OEM requirements and is a direct-fit cooling system replacement for select BMW applications, including BMW X3 and BMW X6 models.

The Four Seasons Thermostat Housing line focuses on engine coolant components that restore proper thermostat function and coolant routing in one assembly. This 86258 housing is a practical choice when servicing a BMW X3 thermostat housing or BMW X6 thermostat housing with an integrated thermostat design.

• Integrated thermostat housing design
• Plastic construction
• Thermostat included
• Meets or exceeds OEM specifications
• Inlet port diameter: 1.51 in
• Overall height: 5.71 in
• Bolt hole center to bolt hole center: 0.91 in
• Gasket or seal not included

Detailed Product Description

Four Seasons 86258 is an engine coolant thermostat housing for vehicles that use an integrated thermostat housing assembly. The plastic housing is engineered for direct replacement service and is listed as meeting or exceeding OEM requirements. With the thermostat included, this part supports a complete thermostat housing service on 2010-2012 BMW X3 and 2011-2012 BMW X6 applications. This part cross-references Genuine 11537586783 for the same application.

Common Cooling System Issues It Can Address

• Cracked or leaking thermostat housing
• Faulty thermostat operation affecting coolant temperature control
• Coolant loss at the housing connection points
• Overheating caused by restricted thermostat function
• Temperature fluctuation from a worn integrated housing assembly

Installation Notes and Tips

Verify the vehicle’s engine coolant thermostat/water outlet assembly configuration before installation. This housing uses an integrated thermostat design and does not include a gasket or seal, so the sealing components required for the repair must be matched to the application. Confirm port size, bolt spacing, and overall housing dimensions against the original part before assembly.

Compatible With 2010-2012 BMW X3, thermostat housing; and 2011-2012 BMW X6, thermostat housing. Use the part number 86258 to confirm the correct Four Seasons replacement during ordering and service.

Quality Assurance

Four Seasons 86258 is built to meet or exceed OEM specifications for the listed BMW applications. The part number 86258 is also referenced under OE-style cross applications, supporting accurate replacement selection for BMW cooling system repair.