Motorad 5511-185 Engine Coolant Thermostat

Engine Coolant Thermostat for OE-Style Cooling Control

The Motorad UltraStat 5511-185 engine coolant thermostat is built for direct cooling-system temperature control in select GM applications. It uses a 185°F opening temperature, includes a rubber seal, and is engineered with stainless steel construction for corrosion resistance and long-term service.

Compatible with 2006-2011 Chevrolet Impala, 2006-2010 Chevrolet Malibu, and other listed Buick, Pontiac, Saturn, and Chevrolet models, this thermostat supports OE-specified temperature control for everyday drivability and stable coolant flow. The Motorad 5511-185 is a practical replacement when the original thermostat is no longer regulating temperature correctly.

Key Features

• 185°F engine coolant thermostat for OE-specified temperature applications
• Heavy-gauge stainless steel construction for corrosion resistance
• BLVT valve technology helps reduce thermal shock to cooling system components
• Includes rubber gasket/seal for installation
• Jiggle pin weep hole for air bleeding during service
• Sealing flange outside diameter: 1.72 in
• Bypass diameter: 1.09 in
• Bypass length: 1.89 in
• Flange thickness: 0.05 in

Product Details

Motorad UltraStat thermostats are built around durable metal construction and controlled opening performance. This 5511-185 thermostat is set to 185 degrees Fahrenheit and is designed to maintain proper coolant circulation as the engine reaches operating temperature. The included rubber seal supports a clean housing interface, while the jiggle pin weep hole helps purge trapped air during refill and service. This part cross-references 46808 and PM185-1155 for the same application.

Fits 2009-2011 Buick Lucerne, N/A; Fits 2006-2011 Chevrolet Impala, N/A; Fits 2006-2010 Chevrolet Malibu, N/A; Fits 2006-2010 Pontiac G6, N/A; Fits 2008-2010 Saturn Vue, N/A; Fits 2006-2009 Chevrolet Uplander, N/A; Fits 2006-2009 Pontiac Montana, N/A; Fits 2007-2008 Saturn Aura, N/A; Fits 2006-2007 Buick Terraza, N/A; Fits 2006-2007 Chevrolet Monte Carlo, N/A; Fits 2006-2007 Saturn Relay, N/A.

Common Cooling System Issues

• Engine running too cool or too hot due to thermostat regulation problems
• Slow warm-up after cold starts
• Temperature fluctuation during normal driving
• Coolant flow irregularities caused by a worn thermostat
• Air trapped in the cooling system after service

Installation Notes and Tips

Verify the thermostat housing and sealing surfaces are clean before installation. Use the included rubber seal and confirm the thermostat is oriented correctly in the housing. Because this part includes a jiggle pin weep hole, position it according to the vehicle service procedure to help air escape during coolant refill. Confirm the 185°F specification matches the original application before installation.

Quality Assurance

Motorad UltraStat thermostats are built with stainless steel construction for corrosion resistance and consistent service life. The BLVT valve design is used to reduce thermal shock in the cooling system, supporting smoother temperature transitions during operation.