Calorstat TH2105.86J Engine Coolant Thermostat

Engine Coolant Thermostat for GM Applications

Calorstat TH2105.86J is a standard engine coolant thermostat built for precise coolant flow control and stable operating temperature. It opens at 187°F (86°C) and includes a rubber gasket seal for a direct replacement service on a wide range of GM vehicles.

Use this thermostat when you need a replacement for GM cooling system service on models such as the Chevrolet Impala, Chevrolet Corvette, and GMC Sierra 1500. The TH2105.86J is also listed for Buick, Cadillac, Pontiac, GMC, Hummer, Isuzu, and Chevrolet truck and SUV applications.

Key Features

• Brand: Calorstat
• Part number: TH2105.86J
• Engine coolant thermostat, standard type
• Start-to-open temperature: 187°F / 86°C
• Gasket or seal included: Yes
• Seal type: gasket
• Seal material: rubber
• Valve outside diameter: 1.22 in.
• Sealing flange outside diameter: 2.12 in.
• Height between flanges: 1.83 in.

Detailed Description

Calorstat TH2105.86J is an OE-style engine coolant thermostat specified for GM cooling system service where a 187°F opening temperature is required. Its standard design, integrated gasket seal, and measured flange dimensions support accurate fitment in the thermostat housing and consistent coolant regulation once installed. This part cross-references Four Seasons 14948 for the same application.

Compatible With 2006-2009 Chevrolet Impala, N/A; 2008-2009 Buick Allure, N/A; 2008-2009 Buick LaCrosse, N/A; 2008-2009 Pontiac G8, N/A; 2004-2008 Chevrolet Corvette, N/A; 2005-2008 Pontiac Grand Prix, N/A; 2005-2007 Cadillac CTS, N/A; and additional GM truck, SUV, and van applications listed below. The TH2105.86J also appears in interchange references including 456187 and 5456187.

What It Helps Fix

• Engine running too cool or too hot due to thermostat wear
• Delayed warm-up and unstable cabin heat output
• Coolant flow control issues caused by a sticking thermostat
• Temperature fluctuation during stop-and-go or highway driving
• Cooling system service on GM vehicles with a 187°F thermostat specification

Installation Notes and Tips

Verify the thermostat housing condition before installation and clean the sealing surface thoroughly. Match the opening temperature and dimensions to the original part, and confirm the gasket seats evenly in the housing. For fitment, this part is listed for 2004-2006 Chevrolet Silverado 1500, 2004-2006 GMC Sierra 1500, 2004-2006 Chevrolet Tahoe, 2004-2006 Cadillac Escalade, 2004-2006 GMC Yukon, 2004-2006 Chevrolet Trailblazer EXT, 2004-2006 Hummer H2, and related GM applications. Additional fitment includes 2004 Chevrolet Express 3500, 2004 Chevrolet Silverado 2500, 2004 GMC Sierra 2500, and 2003 Isuzu Ascender.

Quality Assurance

Calorstat TH2105.86J is listed with OE-recommended and OE-supplier references across GM applications, including notes that Vernet is an OE supplier to GM on selected vehicles. That sourcing context supports a replacement part built to match original cooling system requirements.