Sierra 18-4457 Exhaust Flapper Valve 4 Inch with Stainless Steel Clamp

The Sierra 18-4457 is a 4-inch external exhaust flapper valve designed to protect marine engine exhaust systems from water intrusion. This essential component prevents water from flowing back into the exhaust system when the engine is not running, which could cause serious engine damage.

Key Features:

• 4-inch diameter flapper valve for standard marine exhaust applications
• EPDM (ethylene propylene diene monomer) rubber construction for superior heat and weather resistance
• External mounting design for easy installation and maintenance
• Includes stainless steel clamp for secure, corrosion-resistant attachment
• Prevents backflow of water into the exhaust system
• Designed for marine inboard and sterndrive applications

This exhaust protector valve is a direct replacement part that helps extend engine life by keeping water out of the exhaust manifold and engine block. The EPDM material resists deterioration from saltwater, heat, and UV exposure, making it ideal for demanding marine environments.