Calorstat TH1183.87J Engine Coolant Thermostat

Calorstat TH1183.87J Thermostat Overview

The Calorstat TH1183.87J engine coolant thermostat is an OEM-grade replacement built for precise coolant flow control. It opens at 188°F (87°C) and includes a gasket and seal for a cleaner service fit on select Volvo applications.

Compatible with 1987 Volvo 760, 1990 Volvo 760, and 1990 Volvo 780, this thermostat supports proper engine warm-up and temperature regulation in the cooling system. The TH1183.87J is a direct-fit style thermostat with a jiggle pin weep hole and rubber seal material for dependable sealing at the housing interface.

Key Features

• OEM-grade engine coolant thermostat
• Start-to-open temperature: 188°F / 87°C
• Gasket or seal included
• Jiggle pin weep hole for air bleeding
• Standard thermostat type
• Sealing flange outside diameter: 2.67 in.
• Valve-seat diameter: 68.0 mm
• By-pass valve diameter: 47.6 mm

Detailed Description

Calorstat TH1183.87J is an engine coolant thermostat designed for Volvo cooling system service where accurate opening temperature matters. It is specified to begin opening at 188°F, helping regulate coolant circulation as the engine reaches operating temperature. The included gasket and rubber seal support a proper seal at the thermostat housing, while the jiggle pin weep hole helps purge trapped air during filling and service. This part cross-references 4122.87 and TH11886 for the same application.

Fits 1987 Volvo 760, N/A. Fits 1990 Volvo 760, N/A. Fits 1990 Volvo 780, N/A. Search terms such as Volvo 760 thermostat replacement, 1990 Volvo 780 coolant thermostat, and TH1183.87J thermostat for Volvo cooling repair align with this application.

Common Cooling System Issues

• Engine running cooler or warmer than specified
• Slow warm-up after cold start
• Temperature fluctuation from a sticking thermostat
• Coolant flow control problems in the housing
• Seal leakage at the thermostat interface

Installation Notes and Tips

Install the thermostat with the jiggle pin oriented to allow trapped air to escape during filling. Clean the housing sealing surfaces before installation and verify the gasket seats evenly. Confirm the replacement matches the 188°F / 87°C opening specification and the Volvo 760 or Volvo 780 application before assembly.

Quality Assurance

Calorstat lists this part as OEM grade, with dimensions and sealing features specified for accurate fit and function in the cooling system. The TH1183.87J is built to meet the requirements of the listed Volvo applications.