Mercury – Quicksilver Thermostat Gasket | Cooling System Seal | Marine Composite | 41812

Overview

When you’re working on your MerCruiser’s thermostat, this little gasket is the part that makes the whole job count. The Mercury Marine 41812 Quicksilver Thermostat Gasket seals the housing to keep coolant where it belongs — inside the system, not dripping down your engine. Made for MerCruiser V6 and V8 engines, it’s cut to exact factory specs and built from a durable marine-grade composite that stands up to heat, vibration, and constant exposure to water. It’s one of those parts you don’t notice when it’s doing its job right — but you’ll definitely notice if it’s not.

Key Features

• Purpose: Keeps the thermostat housing sealed tight to maintain proper cooling and prevent leaks.
• Material: Built from high-strength marine composite that resists heat, pressure, and coolant contact.
• Design: Cut precisely to Mercury’s original specifications for a perfect, leak-free fit.
• Performance: Helps your engine stay at the correct operating temperature for better fuel efficiency and smoother performance.
• Durability: Withstands years of heating, cooling, and vibration without warping or cracking.
• Compatibility: Fits MerCruiser V6 and V8 sterndrive and inboard engines.

Engine & Boat Compatibility

• MerCruiser V6 and V8 engines with flat thermostat housings.
• Common on runabouts, cruisers, performance boats, and classic sterndrives.
• Performs equally well in freshwater or saltwater setups.
• Always confirm your thermostat type in your owner’s or service manual before replacing.

Performance & Practical Benefits

The 41812 gasket plays a simple but important role — it keeps coolant pressure stable and stops leaks that can cause overheating. A tight seal means steady temperature control, which helps your MerCruiser run smoother and more efficiently.

Old gaskets can dry out, flatten, or lose their grip over time. Replacing it during a thermostat service takes just a few minutes and can save you from coolant leaks or costly engine wear later. It’s a small fix that brings real peace of mind every time you fire up your boat.

Why Use Mercury OEM Parts

The Quicksilver 41812 is a genuine Mercury Marine gasket, built from the same material and shape your engine came with from the factory. Aftermarket gaskets might look close, but small differences in size or thickness can cause uneven sealing or coolant leaks.

Mercury’s OEM parts are tested for temperature and pressure under real boating conditions, so you know they’ll last. You’re not just buying a gasket — you’re buying a seal you can trust when the engine’s running hot and the water gets rough.

FAQ

Q1: Which engines does this fit?
It fits MerCruiser V6 and V8 engines with standard thermostat housings.

Q2: Why replace it with the thermostat?
Old gaskets flatten and lose their seal, which can cause leaks. It’s best to replace both at once.

Q3: What’s it made from?
A marine-grade composite material designed to handle pressure, heat, and moisture.

Q4: Will it work in saltwater?
Yes — it’s made to last in both salt and freshwater environments.

Q5: Why OEM instead of generic?
OEM gaskets fit exactly and stay sealed longer — cheaper options often don’t.

• Supersessions
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