Four Seasons 85254 Engine Coolant Thermostat Housing

Thermostat Housing for GM Cooling Systems

Four Seasons 85254 is an engine coolant thermostat housing built for select Chevrolet, GMC, Cadillac, Hummer, and Pontiac applications. It is an aluminum thermostat housing with the gasket or seal included and no thermostat installed, making it a direct replacement for service work on the cooling system.

Use this Four Seasons thermostat housing when servicing a leaking, warped, or corroded coolant outlet on vehicles such as the Chevrolet Silverado 1500, GMC Sierra 2500 HD, and Cadillac Escalade. Part number 85254 is made to meet or exceed OEM requirements and is listed for multiple GM truck, SUV, and performance applications.

Key Features

• Aluminum construction for cooling-system durability
• Gasket or seal included for a cleaner service replacement
• Thermostat not included; housing only
• Style: without thermostat
• Meets or exceeds OEM specifications
• Inlet port diameter: 1.307 in.
• Overall height: 2.51 in.
• Flange thickness: 0.395 in.
• Bolt hole center to bolt hole center: 2.93 in. and 3.000 in.

Product Details

Four Seasons Thermostat Housing line focuses on engine coolant components built for accurate fit and dependable sealing. This housing is designed for GM cooling system service where the original thermostat housing has cracked, corroded, or begun to leak. The aluminum body helps maintain a stable mounting surface, while the included gasket or seal supports proper reassembly. This part cross-references ACDelco 12558838 and Gates W5156 for the same application.

What It Helps Fix

• Coolant leaks at the thermostat housing
• Cracked or warped housing surfaces
• Corrosion around the coolant outlet
• Improper sealing after prior cooling-system repairs
• Service issues on GM trucks, SUVs, and performance models

Installation Notes

Fits 1999-2003 Chevrolet Silverado 1500, 1999-2003 GMC Sierra 1500, 2000-2003 Chevrolet Tahoe, 2000-2003 GMC Yukon, and other listed GM applications. Fits 1996-2003 Chevrolet Corvette, 1998-2002 Chevrolet Camaro, and 1998-2002 Pontiac Firebird, w/o Thermostat; Thermostat Housing. Fits 2002-2003 Cadillac Escalade and 2003 Hummer H2, w/o Thermostat; Thermostat Housing. Verify the housing style, inlet diameter, and bolt spacing against the original part before installation. Clean the mating surfaces thoroughly and inspect the thermostat and coolant passages during service.

Quality Assurance

Four Seasons lists this part as meeting or exceeding OEM requirements for the specified applications. Part number 85254 is cataloged for direct replacement use across the confirmed fitment range, including Chevrolet Express 1500, GMC Envoy XL, and Chevrolet Silverado 2500 HD applications.