Calorstat TH4947.81 Engine Coolant Thermostat

Engine Coolant Thermostat for OE-Style Cooling Control

Calorstat TH4947.81 is a standard engine coolant thermostat built to OEM-grade specifications for precise coolant flow control. With a 178.0°F start-to-open temperature, it supports stable operating temperature in a wide range of Ford, Mazda, Volkswagen, Porsche, Volvo, Dodge, and Mercury applications.

This thermostat is a direct-fit cooling system service part for vehicles such as the Ford Explorer, Ford Ranger, and Volkswagen Jetta, where accurate temperature regulation is critical for drivability and engine protection. Part number TH4947.81 is also referenced in OE and aftermarket catalogs for the same application.

Key Features

• Engine coolant thermostat, standard type
• OEM grade construction for OE-style fit and function
• Start to open temperature: 178.0°F
• Sealing flange outside diameter: 2.67 in.
• Height between flanges: 1.02 in.
• Gasket or seal not included
• Calorstat TH4947.81 for cooling system service

Detailed Description

Calorstat TH4947.81 is engineered for vehicles that require an 82°C / 180°F thermostat calibration, including many Ford Explorer and Ford Ranger applications, along with select Mazda B4000, Mercury Mountaineer, and Volkswagen Golf and Jetta models. The thermostat opens at 178.0°F to regulate coolant circulation and help the engine reach and maintain normal operating temperature. Its OEM-grade design supports consistent cooling system performance in applications where temperature control affects fuel efficiency, heater output, and overall engine operation.

This part cross-references Motorad 249-174 for the same application.

What It Helps Address

• Engine running too cool or too warm
• Delayed warm-up after cold starts
• Unstable coolant temperature readings
• Weak cabin heat caused by poor thermostat regulation
• Cooling system service on Ford Explorer, Ford Ranger, and Volkswagen Jetta applications

Installation Notes and Tips

• Verify the thermostat housing and sealing surfaces are clean before installation.
• Replace the thermostat only with the correct temperature specification for the vehicle application.
• Because no gasket or seal is included, confirm the required seal is sourced separately before service.
• Bleed air from the cooling system after installation to help prevent hot spots and inaccurate temperature control.
• Confirm fitment by year, make, model, and opening temperature before ordering.

Quality Assurance

Calorstat TH4947.81 is an OEM-grade thermostat built for direct replacement use in confirmed applications. It is listed across multiple OE and aftermarket part numbers, including TH4947.81, for broad catalog reference and fit verification.