Calorstat TH6851.82 Engine Coolant Thermostat

Engine Coolant Thermostat for Nissan and Infiniti

Calorstat TH6851.82 is a standard engine coolant thermostat built to regulate coolant flow and help the engine reach and maintain operating temperature. With a 180.0 degree start-to-open temperature, it supports stable warm-up and consistent cooling performance in the applications listed below.

• Standard thermostat design for OE-style cooling system service
• Start to open temperature: 180.0 degrees
• Sealing flange outside diameter: 2.51
• Height between flanges: 1.92
• Direct-fit coverage for select Nissan Frontier, Xterra, Quest, Pathfinder, and INFINITI QX4 applications
• Calorstat TH6851.82 cross-references BBB Industries 13948 and Four Seasons 33738 for the same application

Fitment Coverage

• Fits 1999-2004 Nissan Frontier, N/A. Vernet is an OE Supplier to Nissan.
• Fits 2000-2004 Nissan Xterra, N/A. Vernet is an OE Supplier to Nissan.
• Fits 1995-2002 Nissan Quest, N/A. Vernet is an OE Supplier to Nissan.
• Fits 1997-2000 INFINITI QX4, N/A. Vernet is an OE Supplier to Infiniti.
• Fits 1996-2000 Nissan Pathfinder, N/A. Vernet is an OE Supplier to Nissan.

What This Thermostat Helps Address

• Engine running too cool or taking too long to warm up
• Overheating caused by restricted thermostat operation
• Temperature swings that affect drivability and heater output
• Cooling system service on Nissan Frontier, Xterra, Quest, Pathfinder, and INFINITI QX4 models
• Replacement of a worn thermostat during cooling system maintenance

Installation Notes and Tips

Verify the sealing flange outside diameter and height between flanges before installation to confirm the correct match for your cooling system. Clean the thermostat housing and sealing surfaces thoroughly, and inspect the coolant condition, gasket surface, and housing for wear or corrosion before reassembly. Calorstat TH6851.82 should be installed in the correct orientation for proper coolant flow control.

Quality Assurance

Calorstat is associated with Vernet OE supply coverage for Nissan and Infiniti applications, supporting the fitment and specification requirements listed for this thermostat.