Motorad 456-187 Engine Coolant Thermostat

Reliable Engine Coolant Thermostat for Select GM and Isuzu Vehicles

The Motorad Standard 456-187 engine coolant thermostat is designed to maintain optimal engine temperature for a range of Buick, Cadillac, Chevrolet, GMC, Hummer, Isuzu, Pontiac, and Saab models. Engineered to open at 187°F, this thermostat ensures efficient coolant flow and engine performance.

• Sealing flange outside diameter: 2.13 inches
• Height between flanges: 1.79 inches
• Overall height: 2.56 inches
• Standard type thermostat with jiggle pin weep hole
• Includes rubber gasket with O-ring seal for secure fit
• Bypass diameter: 1.46 inches; bypass length: 1.84 inches
• Flange thickness: 0.05 inches
• Start to open temperature: 187°F
• One seal included; installation tool not included

About the Motorad Standard Product Line

The Motorad Standard line offers dependable replacement parts designed to meet original equipment specifications. This engine coolant thermostat from the Standard series provides consistent temperature regulation and reliable sealing, making it suitable for various GM and Isuzu vehicles. The inclusion of a rubber gasket and O-ring seal helps prevent leaks and ensures a proper fit within the cooling system.

Product Details and Specifications

This Motorad 456-187 thermostat features a sealing flange outside diameter of 2.13 inches and a height between flanges of 1.79 inches, fitting precisely within the cooling housing. The thermostat opens at 187 degrees Fahrenheit, allowing coolant to circulate once the engine reaches optimal operating temperature. The jiggle pin weep hole aids in air bleeding, preventing air pockets in the cooling system. The bypass diameter and length (1.46 inches and 1.84 inches respectively) support proper coolant flow during warm-up phases. The included rubber gasket with an O-ring seal ensures a tight, leak-free installation.

Compatible Vehicles and Applications

• Buick Allure, LaCrosse, Lucerne
• Cadillac CTS, Escalade, Escalade ESV, Escalade EXT
• Chevrolet Avalanche 1500, Camaro, Corvette, Express 1500/2500/3500, Impala, Monte Carlo, Silverado 1500/2500/3500, Suburban 1500/2500, Tahoe, Trailblazer, Trailblazer EXT
• GMC Envoy, Envoy XL, Envoy XUV, Sierra 1500/2500/3500, Yukon, Yukon XL 1500/2500
• Hummer H2
• Isuzu Ascender
• Pontiac G8, Grand Prix, GTO, Firebird
• Saab 9-7x

Common Issues Addressed by This Thermostat

• Engine overheating due to thermostat failure
• Coolant leaks from worn or damaged seals
• Poor engine warm-up performance
• Air trapped in the cooling system causing temperature fluctuations
• Inconsistent coolant flow affecting engine efficiency

Installation Notes and Tips

Ensure the engine is cool before beginning installation. Remove the old thermostat and clean the housing surface thoroughly to prevent leaks. This thermostat includes a rubber gasket with an O-ring seal; verify the seal is properly seated during installation. The jiggle pin weep hole should be positioned correctly to allow air to escape. No installation tool is included, so use appropriate hand tools and follow vehicle-specific service manual instructions for torque specifications.

Quality Assurance and Warranty

Motorad Standard thermostats are manufactured to meet OEM standards for fit and function. The included rubber gasket and O-ring seal provide reliable sealing to prevent coolant leaks. While specific warranty details are not provided, Motorad products typically adhere to industry quality controls to ensure durability and performance in compatible Buick, Cadillac, Chevrolet, GMC, Hummer, Isuzu, Pontiac, and Saab vehicles.