Calorstat TH6529.87J Engine Coolant Thermostat

Engine Coolant Thermostat for Audi V6 Cooling Systems

Calorstat TH6529.87J is a standard engine coolant thermostat built for precise coolant flow control in select Audi applications. It opens at 188.0°F and includes an O-ring seal, gasket or seal, and a jiggle pin weep hole for proper venting during service.

Fits 2002-2004 Audi A6 Quattro and 2002-2003 Audi S6. This part cross-references 077121113B and 820415 for the same application.

Key Features

• Standard engine coolant thermostat for regulated engine warm-up and operating temperature control
• Start to open temperature: 188.0°F
• Gasket or seal included for service replacement
• O-ring seal type with rubber seal material
• Jiggle pin weep hole for air bleed during installation and coolant circulation
• Sealing flange outside diameter: 2.63 in.
• Valve-seat diameter: 67.0 mm
• By-pass valve diameter: 35.0 mm
• Calorstat TH6529.87J for select Audi cooling system applications

Detailed Description

Calorstat TH6529.87J is an engine coolant thermostat for vehicles that require stable coolant regulation and OE-style fitment. The thermostat’s 188.0°F opening point helps maintain the engine at its intended operating range, while the included O-ring seal and gasket or seal support a proper housing seal during replacement. The jiggle pin weep hole helps purge trapped air from the cooling system, which is important for consistent coolant flow after service. This thermostat is listed for 2002-2004 Audi A6 Quattro and 2002-2003 Audi S6, making it a direct-match service part for those applications. Use TH6529.87J when replacing a worn thermostat in Audi cooling system repairs.

Common Problems This Part May Address

• Engine running too cool or taking too long to reach operating temperature
• Engine overheating caused by a thermostat that no longer opens correctly
• Coolant temperature fluctuations during driving
• Coolant leaks at the thermostat housing seal area
• Air trapped in the cooling system after thermostat service

Installation Notes and Tips

Verify the thermostat orientation and housing condition before installation. Clean the sealing surfaces thoroughly and replace any damaged housing components before reassembly. Because this thermostat includes a jiggle pin weep hole and O-ring seal, align the part correctly and ensure the seal seats evenly to prevent leaks. After installation, refill and bleed the cooling system according to the vehicle service procedure for the Audi A6 Quattro or Audi S6.

Quality Assurance

Calorstat is listed as an OE supplier to Audi for these applications, supporting the fitment and specification match for TH6529.87J in select Audi cooling systems.