Sierra 18-2917-9 Marine Thermostat Gasket for MerCruiser GM V6 V8 Engines - 2 Pack

The Sierra 18-2917-9 is a thermostat housing-to-intake-manifold gasket designed specifically for marine engines. Sold as a pack of two, these gaskets are manufactured to meet or exceed OEM specifications, providing a reliable, leak-free seal at the thermostat housing.

Sierra engineered this gasket for use with GM V-6 and V-8 marine engines, making it a direct replacement for MerCruiser and OMC applications. Grounding washers are included. The gasket is constructed from premium, heat-resistant materials built to withstand the demanding conditions of marine engine cooling systems.

Key Features:

• Pack of 2 thermostat gaskets with grounding washers
• Seals the thermostat housing to the intake manifold
• Heat-resistant, premium-grade construction
• Meets or exceeds OEM fit and performance standards
• Direct OEM replacement — no modification required

OEM Cross References:

• MerCruiser: 27-53045, 27-530451
• OMC / Johnson / Evinrude: 312797, 3701777
• GLM: 31560
• Mallory: 9-60007, 9-60007-10

Replace thermostat gaskets whenever servicing the thermostat to prevent coolant leaks and maintain proper engine cooling system integrity. Sierra part number 18-2917 is also available sold individually.