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Genuine GM OEM Duramax Rear Engine Coolant Thermostat – Part #12680456 (185°F)
Keep your 6.6L Duramax running at the correct operating temperature with this genuine GM Original Equipment coolant thermostat. Designed specifically for the L5P (and compatible L5D) Duramax engines, this 185°F thermostat precisely regulates coolant flow through the radiator so the engine reaches and maintains its optimal temperature for performance, efficiency, and longevity.
Key Features
- Genuine GM / ACDelco Original Equipment part (OEM #12680456)
- Opens at 185°F (85°C)
- Direct-fit replacement for the factory thermostat
- Manufactured to exact GM specifications for proper fit, form, and function
- Helps prevent overheating and maintains consistent engine temperature under load, towing, and everyday driving
Fitment
2017–2026 L5P
2019-2024 L5D
Note: This is the 185° thermostat. Many L5P & L5D applications use a dual-thermostat housing (180° + 185°). Confirm which position you need before ordering. Gasket/seal is sold separately.
Replace a sticking or failed thermostat with the exact OEM component your Duramax was designed for. Proper cooling system function is critical on these high-output diesels—especially when towing or running in extreme conditions.
Genuine GM OEM Duramax Rear Engine Coolant Thermostat – Part #12680456 (185°F)
Keep your 6.6L Duramax running at the correct operating temperature with this genuine GM Original Equipment coolant thermostat. Designed specifically for the L5P (and compatible L5D) Duramax engines, this 185°F thermostat precisely regulates coolant flow through the radiator so the engine reaches and maintains its optimal temperature for performance, efficiency, and longevity.
Key Features
Genuine GM / ACDelco Original Equipment part (OEM #12680456)
Opens at 185°F (85°C)
Direct-fit replacement for the factory thermostat
Manufactured to exact GM specifications for proper fit, form, and function
Helps prevent overheating and maintains consistent engine temperature under load, towing, and everyday driving
Fitment
2017–2026 L5P
2019-2024 L5D
Note: This is the 185° thermostat. Many L5P & L5D applications use a dual-thermostat housing (180° + 185°). Confirm which position you need before ordering. Gasket/seal is sold separately.
Replace a sticking or failed thermostat with the exact OEM component your Duram[...]
Genuine GM OEM Duramax Rear Engine Coolant Thermostat – Part #12680456 (185°F)
Keep your 6.6L Duramax running at the correct operating temperature with this genuine GM Original Equipment coolant thermostat. Designed specifically for the L5P (and compatible L5D) Duramax engines, this 185°F thermostat precisely regulates coolant flow through the radiator so the engine reaches and maintains its optimal temperature for performance, efficiency, and longevity.
Key Features
- Genuine GM / ACDelco Original Equipment part (OEM #12680456)
- Opens at 185°F (85°C)
- Direct-fit replacement for the factory thermostat
- Manufactured to exact GM specifications for proper fit, form, and function
- Helps prevent overheating and maintains consistent engine temperature under load, towing, and everyday driving
Fitment
2017–2026 L5P
2019-2024 L5D
Note: This is the 185° thermostat. Many L5P & L5D applications use a dual-thermostat housing (180° + 185°). Confirm which position you need before ordering. Gasket/seal is sold separately.
Replace a sticking or failed thermostat with the exact OEM component your Duramax was designed for. Proper cooling system function is critical on these high-output diesels—especially when towing or running in extreme conditions.