Sierra Marine Thermostats

5.0 out of 5 stars 5 Customer Reviews

Sierra Marine thermostats are exact replacements made of the same high-quality materials as your factory original to provide accurate fit and function for reliable performance. They are available in a wide range of make/model and engine applications—order the thermostat model suited to your needs.

Showing In Stock Items. Show All 16 Items.

Results 1 - 15 of 15

Sierra Marine Thermostats 18-3668

Thermostat Kit, Gasket, O-ring, Copper/Stainless Steel, 142 Degree, 1983 and up GM V6 and V8 engines with standard cooling, Kit

Part Number: RRA-18-3668

Not Yet Reviewed

Estimated Ship Date: Tomorrow

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Sierra Marine Thermostats 18-3677

Thermostat Kit, Gasket, O-ring, Copper/Stainless Steel, 160 Degree, OMC 4.3, 5.0, 5.8, Kit

Part Number: RRA-18-3677

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Estimated Ship Date: Tomorrow

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Sierra Marine Thermostats 18-3551

Thermostat, 142 Degree, 2.125 in. O.D., 1.5 in. Height, Mercruiser, Mercury Marine, Chrysler, Each

Part Number: RRA-18-3551

Not Yet Reviewed

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Sierra Marine Thermostats 18-3606

Thermostat, 130 Degree, Mercury Marine, Pair

Part Number: RRA-18-3606

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Dec 12, 2025 if ordered today

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Estimated Ship Date: Dec 12, 2025 if ordered today

Sierra Marine Thermostats 18-3535

Thermostat, 130 Degrees Opening Temperature, Plastic/Steel, Mercury Marine, Each

Part Number: RRA-18-3535

5.0 out of 5 stars ( 3 )

Estimated Ship Date: Tomorrow

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Sierra Marine Thermostats 18-3550

Thermostat, 140 Degree, Mercruiser, Mercury Marine, Chrysler, Each

Part Number: RRA-18-3550

Not Yet Reviewed

Estimated Ship Date: Dec 12, 2025 if ordered today

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Estimated Ship Date: Dec 12, 2025 if ordered today

Sierra Marine Thermostats 18-3552

Thermostat, 160 Degree, Mercruiser, Mercury Marine, Crusader, Each

Part Number: RRA-18-3552

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Dec 12, 2025 if ordered today

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Estimated Ship Date: Dec 12, 2025 if ordered today

Sierra Marine Thermostats 18-3540

Thermostat, Outboard, Yamaha, Each

Part Number: RRA-18-3540

Not Yet Reviewed

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Sierra Marine Thermostats 18-3632

Thermostat, Outboard, Yamaha, Each

Part Number: RRA-18-3632

Not Yet Reviewed

Estimated Ship Date: Tomorrow

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Sierra Marine Thermostats 18-3660

Thermostat, 170 Degrees Opening Temperature, Volvo Penta, Each

Part Number: RRA-18-3660

Not Yet Reviewed

Estimated Ship Date: Tomorrow

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Sierra Marine Thermostats 18-3541

Thermostat, Outboard, Yamaha, Each

Part Number: RRA-18-3541

Not Yet Reviewed

Estimated Ship Date: Tomorrow

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Sierra Marine Thermostats 18-3631

Thermostat With Housing, Plastic/Steel, 135-300 Mercury Verado, Each

Part Number: RRA-18-3631

Not Yet Reviewed

Estimated Ship Date: Dec 12, 2025 if ordered today

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Estimated Ship Date: Dec 12, 2025 if ordered today

Sierra Marine Thermostats 18-3672

Thermostat, Gasket, Outboard, Copper/Brass, Mercury Marine, Kit

Part Number: RRA-18-3672

Not Yet Reviewed

Estimated Ship Date: Dec 12, 2025 if ordered today

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Estimated Ship Date: Dec 12, 2025 if ordered today

Sierra Marine Thermostats 18-3673

Thermostat, Gaskets, Springs, Outboard, Johnson/Evinrude, Kit

Part Number: RRA-18-3673

Not Yet Reviewed

Estimated Ship Date: Dec 12, 2025 if ordered today

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Estimated Ship Date: Dec 12, 2025 if ordered today

Sierra Marine Thermostats 18-3536

Thermostat, 143 Degree, Mercury Marine, Each

Part Number: RRA-18-3536

Not Yet Reviewed

Estimated Ship Date: Dec 12, 2025 if ordered today

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Estimated Ship Date: Dec 12, 2025 if ordered today

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