Engineered Marine Products 75-00421 Thermostat Kit 160 Degree OMC Stern Drive

The Engineered Marine Products (EMP) 75-00421 is a complete 160-degree thermostat kit engineered for OMC stern drive and inboard marine engines. Designed as a direct replacement for original equipment, this kit maintains proper engine operating temperature to protect performance and prevent overheating.

This thermostat is built to resist the significant variations in coolant pressure that occur at high RPMs, where fluctuations in both temperature and pressure can prevent a standard thermostat from opening at its rated temperature. The all-brass and copper construction ensures reliable, consistent opening at exactly 160°F regardless of engine speed.

Key Features:

• Opens consistently at 160°F for precise engine temperature control
• All-brass and copper construction for superior durability and corrosion resistance
• Engineered to handle high-RPM coolant pressure fluctuations
• Complete kit includes thermostat, housing gasket, and thermostat gasket
• Direct OEM replacement fit — no modifications required

Replaces OEM Part Numbers:

• OMC 383307
• Mallory 9-43156
• GLM 13430
• Sierra 18-3653

Maintaining a properly functioning thermostat is essential to marine engine health. A thermostat stuck open causes the engine to run too cool and lose power and efficiency, while one stuck closed can lead to dangerous overheating. This EMP kit provides everything needed for a complete, reliable thermostat replacement.