Sierra 18-3667 Marine Thermostat Kit, 160 Degree, White, for Mercruiser Stern Drive

The Sierra 18-3667 Marine Thermostat Kit is a complete replacement kit built for Mercruiser stern drive engines. Rather than sourcing a thermostat and gasket separately, this kit bundles both components so the cooling system repair can be completed in a single job. The kit includes a 160 degree thermostat (Sierra 18-3555, OE# 99155A1) that regulates engine coolant temperature to keep the engine operating in its proper range, along with a matching thermostat cover gasket (Sierra 18-2555, OE# 27-89656-1) that seals the thermostat housing to prevent coolant leaks after installation.

Sierra engineers its cooling system parts to meet or exceed the specifications of the original equipment they replace, and this kit is manufactured to the same standard for reliable, drop-in service on Mercruiser stern drive applications. The thermostat kit is finished in white and is sold as a matched set so both wear parts are replaced together, reducing the chance of a repeat leak or overheating issue from reusing an old gasket alongside a new thermostat.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3667
• Kit Type: Thermostat Kit
• Kit Contents: Thermostat (Sierra 18-3555, OE# 99155A1); Thermostat Cover Gasket (Sierra 18-2555, OE# 27-89656-1)
• Temperature Rating: 160 degrees F
• Color: White
• Application: Mercruiser Stern Drive
• UPC: 030999316301
• Weight: 0.16 pounds

Replaces (OEM)

• GLM 13420

Frequently Asked Questions

What is included in the Sierra 18-3667 Thermostat Kit? The Sierra 18-3667 kit includes a 160 degree thermostat (Sierra 18-3555) and a matching thermostat cover gasket (Sierra 18-2555), so both wear parts can be replaced together in one job.

What temperature rating is the thermostat in kit 18-3667? It is rated at 160 degrees Fahrenheit, which sets the coolant temperature at which the thermostat opens to regulate engine cooling.

What does the 18-3667 thermostat kit fit? The Sierra 18-3667 Thermostat Kit is designed for Mercruiser stern drive engines.

What OEM part does the 18-3667 kit cross-reference to? The Sierra 18-3667 Thermostat Kit is interchangeable with GLM 13420.

What color is the Sierra 18-3667 thermostat kit? The kit is white.

How much does the Sierra 18-3667 kit weigh? This thermostat kit weighs 0.16 pounds.

Do I need to buy the gasket separately when replacing the thermostat? No, the Sierra 18-3667 kit already includes both the 18-3555 thermostat and the 18-2555 thermostat cover gasket, so no separate gasket purchase is needed.

Is the Sierra 18-3667 kit genuine Sierra or aftermarket? It is a genuine Sierra part, manufactured to meet or exceed the original equipment specifications for Mercruiser stern drive cooling systems.

What is the UPC for the Sierra 18-3667 Thermostat Kit? The UPC for this Sierra thermostat kit is 030999316301.

Why replace the thermostat and gasket together instead of just the thermostat? Replacing both components in the Sierra 18-3667 kit at the same time helps prevent a coolant leak from an old, worn gasket after a new thermostat has been installed.