Mercury – Quicksilver Thermostat Housing Gasket | Cooling System Seal | Marine-Grade Composite | 530451

Overview

Keeping your cooling system sealed tight is key to consistent engine temperatures and smooth performance. The Mercury Marine 530451 Quicksilver Thermostat Housing Gasket is built for V6 and V8 MerCruiser sterndrives and inboard engines made by General Motors, as well as similar engines used by OMC and Volvo Penta. Made from durable, heat-resistant composite material, this gasket ensures a tight seal between the housing surfaces to prevent leaks and pressure loss. It’s a simple, reliable way to keep your cooling system working efficiently and your engine protected.

Key Features

• Purpose: Seals the thermostat housing to prevent coolant leaks and maintain proper system pressure.
• Material: Made from marine-grade composite that resists heat, pressure, and coolant exposure.
• Design: Cut to OEM Mercury dimensions for a perfect fit and easy installation.
• Durability: Handles temperature swings, vibration, and constant contact with coolant.
• Performance: Keeps the cooling system airtight for stable operating temperatures and efficiency.
• Compatibility: For GM-based V6 and V8 MerCruiser sterndrives and inboard engines, plus OMC and Volvo Penta engines with matching CID.

Engine & Boat Compatibility

• MerCruiser V6 sterndrive and inboard engines by General Motors
• MerCruiser V8 sterndrive and inboard engines by General Motors
• OMC sterndrive and inboard engines of matching GM size
• Volvo Penta North America sterndrive and inboard engines of matching GM size

Performance & Real-World Benefits

The 530451 gasket provides a tight, reliable seal between thermostat housing components, keeping your cooling system leak-free and running efficiently. A worn gasket can cause coolant loss and uneven engine temperatures — problems that can quickly turn into bigger repairs.

This Mercury OEM gasket is built to handle the constant heat and vibration of marine use. It compresses evenly, stays flexible under pressure, and won’t crack or harden over time. Replacing it during thermostat service is an easy way to protect your engine and keep it running cool trip after trip.

Why Choose Mercury OEM

The Quicksilver 530451 is a genuine Mercury Marine part, designed to match the exact materials, cut, and fit of the factory original. Aftermarket gaskets may look similar but often use lower-quality materials that can shrink or leak under heat.

Mercury’s OEM gaskets are built for long life and consistent sealing under marine conditions — a small investment that delivers lasting protection and peace of mind.

FAQ

Q1: Which engines does this gasket fit?
It fits GM-based MerCruiser V6 and V8 engines, and also works with OMC and Volvo Penta engines of the same displacement.

Q2: What’s it made from?
It’s made from a marine-grade composite designed to resist heat and coolant exposure.

Q3: Why replace the gasket?
Old gaskets can harden or crack, allowing coolant to leak and reducing cooling efficiency.

Q4: Can it handle saltwater use?
Yes — it’s built for both saltwater and freshwater environments.

Q5: Why use OEM instead of aftermarket?
Mercury OEM gaskets guarantee the correct fit, sealing strength, and long-lasting performance in tough marine conditions.