Motorad 269-174 Engine Coolant Thermostat

Engine Coolant Thermostat for Mercedes-Benz

Motorad Standard 269-174 is an engine coolant thermostat built to OE specifications for Mercedes-Benz cooling systems that use a separate thermostat and housing. The 174°F opening temperature helps regulate coolant flow at the factory-specified setting, supporting stable engine operating temperature in demanding daily driving conditions.

Designed for Mercedes-Benz CL500, S420, S500, SL500, E420, E500, 400E, 500E, 400SEL, 500SEL, 500SEC, 500SL, 400SE, 420SEL, 560SEC, 560SEL, 560SL, 380SE, 380SL, and 380SEC applications, Motorad 269-174 is a direct-fit thermostat for a wide range of classic and late-model V8 and inline cooling systems.

Key Features

• 174°F start-to-open temperature for OE-specified coolant control
• Copper case and wax compound for quick response to coolant temperature changes
• Offset design with air relief valve where applicable
• OEM-style seals included where applicable
• Jiggle pin weep hole for air bleeding during service
• Standard thermostat design for separate thermostat and housing setups
• Motorad Standard line focuses on OE-spec replacement coverage

Detailed Description

The Motorad Standard line is built for straightforward OE replacement service, using OEM-quality materials and manufacturing processes. Part number 269-174 follows factory-style dimensions, including a 2.64 in sealing flange outside diameter, 1.93 in height between flanges, 2.75 in overall height, and a 0.06 in flange thickness. The bypass measures 1.14 in in diameter and 1.73 in in length, helping maintain proper coolant routing in the original Mercedes-Benz thermostat housing design.

This thermostat cross-references Stant 14578 for the same application. It is a practical choice for Mercedes-Benz 174°F thermostat service on models such as the 1994-1999 S500, 1994-1998 SL500, and 1986-1991 560SEL, where OE temperature control is required.

What It Helps Address

• Engine running too cool or too warm due to thermostat wear
• Delayed coolant flow regulation after cold starts
• Temperature fluctuation from a sticking thermostat
• Cooling system service on Mercedes-Benz vehicles with separate thermostat and housing
• Air trapped in the cooling circuit during thermostat replacement

Installation Notes and Tips

Verify the 174°F specification before installation and confirm the vehicle uses a separate thermostat and housing. Inspect the housing, sealing surfaces, and coolant condition before reassembly. Because no gasket or seal is included, reuse only serviceable components or install the correct replacement seal for the application. The jiggle pin weep hole should be oriented to help purge trapped air during filling and bleeding.

Quality Assurance

Motorad manufactures this thermostat to OEM quality materials and safety standards as an OE supplier, with OE specifications and processes used in production. The copper case and wax element are selected for consistent temperature response in automotive cooling systems.