Calorstat TH1439.87J Engine Coolant Thermostat

Engine Coolant Thermostat for VW and Audi

The Calorstat TH1439.87J engine coolant thermostat is an OEM-grade replacement for select Volkswagen and Audi applications. It opens at 188°F (87°C) to help regulate coolant flow and maintain stable operating temperature in older VW and Audi cooling systems.

• Brand: Calorstat
• Part number: TH1439.87J
• Engine coolant thermostat, standard type
• OEM grade construction
• Start-to-open temperature: 188°F / 87°C
• Gasket or seal included: Yes
• Seal type: gasket O-ring
• Seal material: rubber + paper
• Sealing flange outside diameter: 2.12 in.
• By-pass valve diameter: 35.0 mm
• Valve-seat diameter: 53.9 mm

Fitment and Application Details

Compatible with a wide range of Volkswagen and Audi cooling system applications, including Fits 1985-1994 Volkswagen Golf, N/A; Fits 1981-1994 Volkswagen Jetta, N/A; Fits 1990-1994 Volkswagen Passat, N/A; Fits 1985-1993 Volkswagen Cabriolet, N/A; Fits 1987-1993 Volkswagen Fox, N/A; Fits 1990-1992 Volkswagen Corrado, N/A; Fits 1988-1990 Audi 80, N/A; Fits 1988 Audi 90, N/A; Fits 1986-1987 Audi 4000, N/A; Fits 1985-1987 Audi 4000 Quattro, N/A; Fits 1980-1985 Audi 4000, N/A; Fits 1982-1985 Volkswagen Quantum, N/A; Fits 1980-1984 Volkswagen Rabbit Convertible, N/A; Fits 1980-1983 Volkswagen Rabbit Pickup, N/A.

This part cross-references Four Seasons 17888 and Motorad 234-192 for the same application.

Key Features

• Direct-fit thermostat for cooling system temperature control
• OEM recommended application coverage for select VW and Audi models
• 188°F opening temperature for proper warm-up and coolant regulation
• Includes gasket/seal for installation
• Standard thermostat design for common housing applications

What This Thermostat Helps Address

• Engine running too cool or too hot
• Slow warm-up after cold starts
• Temperature fluctuation from a sticking thermostat
• Coolant flow issues related to worn thermostat components
• Cooling system service on aging Volkswagen and Audi vehicles

Installation Notes and Tips

Verify the thermostat housing, seal style, and opening temperature before installation. Clean the sealing surfaces thoroughly and inspect the housing for corrosion or warping so the gasket O-ring can seat correctly. Confirm the bypass valve and valve-seat dimensions match the original part during service on Volkswagen Golf, Jetta, Passat, Cabriolet, Fox, Corrado, and Audi 4000-family applications.

Quality Assurance

Calorstat TH1439.87J is built to OEM grade specifications for the listed applications and uses a gasket O-ring seal with rubber and paper sealing materials. The 188°F opening specification supports factory-style coolant temperature control in compatible Volkswagen and Audi vehicles.