Motorad 523-190 Engine Coolant Thermostat

Engine Cooling Control for GM Applications

Motorad 523-190 is a standard engine coolant thermostat built for OE-style temperature control in a wide range of Chevrolet, GMC, Cadillac, Buick, Hummer, and Saab applications. It opens at 187°F and includes an O-ring seal, jiggle pin weep hole, and OEM-style sealing features for service replacement work.

Use this thermostat when you need consistent coolant flow regulation in vehicles such as the Chevrolet Silverado 2500 HD, GMC Sierra 3500 HD, and Chevrolet Corvette. The Motorad Standard line focuses on OE-spec construction for direct-fit cooling system service.

Key Features

• Part number 523-190
• 187°F start-to-open temperature
• Standard thermostat design
• Copper case with wax compound for responsive temperature control
• Includes gasket/seal with rubber O-ring sealing material
• Jiggle pin weep hole for air relief during filling and service
• Offset design and OEM-style seals where applicable
• Built to OEM specifications and processes

Product Details

This engine coolant thermostat regulates coolant flow based on temperature so the engine can reach and maintain its intended operating range. Motorad manufactures the 523-190 with OEM-quality materials and OE-supplier standards, using a copper case and wax element to react quickly to coolant temperature changes. The 187°F calibration matches OE-specified service needs for many GM trucks, SUVs, performance cars, and vans, including Chevrolet Silverado 1500, GMC Yukon, and Cadillac Escalade applications. This part cross-references Stant 15158 for the same application.

Common Problems It Can Help Address

• Engine running too cool or taking too long to warm up
• Temperature fluctuation caused by a worn thermostat
• Coolant flow issues after cooling system service
• Air trapped in the cooling system during refill
• Loss of proper temperature regulation in high-load driving

Installation Notes and Tips

Install the thermostat with the sealing surfaces clean and free of old gasket material. Verify the housing and mating surfaces before assembly, and follow the vehicle service procedure for coolant refill and air bleeding. The jiggle pin weep hole should be oriented according to the manufacturer’s installation guidance when applicable. Confirm the 187°F specification and vehicle application before installation on Chevrolet Silverado, GMC Sierra, and related GM platforms.

Quality Assurance

Motorad Standard thermostats are manufactured to OEM specifications and safety standards by an OE supplier. The 523-190 is built for demanding automotive cooling systems and uses OEM-style materials and sealing features to support reliable service replacement.