Calorstat TH4856.88J Engine Coolant Thermostat

Engine Coolant Thermostat for Volvo Cooling Systems

Calorstat TH4856.88J is an OEM-grade engine coolant thermostat built for precise temperature control in Volvo cooling systems. It opens at 190°F (88°C) and includes a gasket and rubber seal for a direct-fit service replacement.

Compatible With Volvo 240, 740, 745, 760, 780, and 940 applications, this thermostat supports stable coolant flow control for classic Volvo engines. The TH4856.88J part number is also a useful reference when cross-shopping thermostat replacements for these vehicles.

Key Features

• OEM-grade standard thermostat for engine cooling service
• Start-to-open temperature: 190°F / 88°C
• Gasket included with rubber seal material
• Jiggle pin weep hole for air bleeding during service
• By-pass valve diameter: 29.0 mm
• Valve-seat diameter: 54.0 mm
• Sealing flange outside diameter: 2.12 in
• Height between flanges: 0.51 in

Detailed Description

Calorstat TH4856.88J is an engine coolant thermostat engineered for Volvo cooling system service where accurate opening temperature matters. It begins opening at 190°F and uses an OEM-grade standard design with a gasket and rubber seal to support proper housing sealing. The jiggle pin weep hole helps purge trapped air during refill and maintenance, while the bypass valve and valve-seat dimensions support correct coolant routing in the thermostat housing.

This part cross-references Stant 48078 for the same application. It is a practical replacement choice for Volvo 240, Volvo 740, Volvo 760, Volvo 780, Volvo 745, and Volvo 940 thermostat service, and the TH4856.88J part number should be matched carefully against the original unit and housing dimensions.

What It Helps Address

• Engine running too cool or taking too long to reach operating temperature
• Overheating caused by a thermostat that is stuck closed or opening late
• Temperature fluctuation from inconsistent coolant flow control
• Air pockets in the cooling system after thermostat service
• Leaking thermostat housing seal or gasket interface

Installation Notes and Tips

Verify the thermostat opening temperature, flange dimensions, and bypass valve size before installation. Clean the housing mating surfaces thoroughly, install the included gasket and seal correctly, and refill the cooling system according to Volvo service procedures. After installation, bleed air from the system and confirm normal operating temperature during a road test.

Quality Assurance

Calorstat lists this thermostat as OEM grade, indicating a specification level intended to match original equipment requirements for fit and temperature control. The TH4856.88J is built for direct replacement use in the listed Volvo applications.