Motorad 251-185 Engine Coolant Thermostat

Reliable Engine Coolant Thermostat for Mercedes-Benz Models

The Motorad Standard 251-185 engine coolant thermostat is designed to maintain optimal engine temperature for select Mercedes-Benz vehicles. Engineered to open at 185 degrees Fahrenheit, this thermostat ensures efficient coolant flow and engine performance.

• Sealing flange outside diameter: 2.64 inches
• Height between flanges: 1.44 inches
• Standard type thermostat with jiggle pin weep hole
• Bypass diameter: 1.64 inches; bypass length: 0.97 inches
• Flange thickness: 0.06 inches
• Start to open temperature: 185°F
• Compatible with Mercedes-Benz 300D, 300SD, 300SDL, 300TD, 350SD, 350SDL, E300, and S350

Detailed Product Description

The Motorad Standard 251-185 thermostat is a precision-engineered component designed to regulate coolant flow in Mercedes-Benz engines. Its 185-degree Fahrenheit opening temperature helps maintain the engine within the ideal operating range, preventing overheating and promoting fuel efficiency. The thermostat features a jiggle pin weep hole to allow air to escape from the cooling system, reducing the risk of air pockets that can cause temperature fluctuations. With a sealing flange outside diameter of 2.64 inches and a flange thickness of 0.06 inches, this thermostat fits securely within the cooling housing. The bypass diameter of 1.64 inches and length of 0.97 inches facilitate proper coolant circulation during engine warm-up.

About the Motorad Standard Product Line

The Standard line from Motorad offers dependable, OEM-quality replacement parts designed to meet original equipment specifications. This line focuses on delivering consistent performance and fitment for a range of vehicles, including Mercedes-Benz models. The 251-185 thermostat exemplifies the Standard line’s commitment to precision and reliability without additional accessories such as gaskets or installation tools, allowing for straightforward integration into existing cooling systems.

Common Applications and Issues Addressed

• Maintains proper engine temperature for Mercedes-Benz 300D, 300SD, 300SDL, 300TD, 350SD, 350SDL, E300, and S350 models
• Prevents engine overheating by opening coolant flow at 185°F
• Reduces risk of coolant bypass issues with precise bypass diameter and length
• Eliminates air pockets in the cooling system via jiggle pin weep hole
• Replaces faulty or stuck thermostats causing poor engine performance

Installation Notes and Tips

This thermostat does not include a gasket or installation tool, so ensure the existing gasket is inspected and replaced if necessary. Proper sealing flange alignment is critical to prevent coolant leaks. The jiggle pin should be positioned at the highest point to allow air to escape during installation. Verify compatibility with your specific Mercedes-Benz model before installation.

Quality Assurance and Warranty

Motorad Standard thermostats are manufactured to meet strict quality standards for durability and performance. While no specific warranty information is provided, Motorad products typically adhere to industry norms for replacement parts. Always consult product documentation or supplier details for warranty coverage.