Sierra 18-0182-9 Thermostat Gasket, Pack of 2 - Fits Johnson/Evinrude 200-235 HP Outboards

The Sierra 18-0182-9 Thermostat Gasket is a replacement gasket for the thermostat housing on select Johnson/Evinrude outboard motors, sold as a pack of 2 so you have a spare on hand or can service both cylinder banks in one job. The gasket seals the thermostat housing to the cylinder head, maintaining proper cooling system pressure and preventing water leakage around the thermostat during operation. It is round in shape with a multi-colored appearance and is built to meet or exceed the quality of the original equipment part it replaces.

This gasket is designed for Johnson/Evinrude outboards rated at 200 HP (1977-83) and 235 HP (1978-85). It is also cross-referenced to several other aftermarket and OEM part numbers, making it a straightforward swap for boat owners and marine technicians sourcing a replacement gasket by an equivalent part number. Each pack ships as a lightweight, low-cost maintenance item intended to be replaced any time the thermostat housing is removed or serviced, ensuring a proper seal and preventing coolant leaks after reassembly.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0182-9
• Product Type: Thermostat Gasket
• Pack Quantity: 2
• Shape: Round
• Color: Multi-colored
• UPC: 808282161484
• Weight: 0.01 pounds
• OEM Cross Reference: GLM 30610, Evinrude/Johnson 310058, Mallory 9-60002, Mercury 27-62386, 27-62386001

Fitment

• Johnson/Evinrude 200 HP outboards, 1977-83
• Johnson/Evinrude 235 HP outboards, 1978-85

Replaces (OEM)

• GLM 30610
• Evinrude/Johnson 310058
• Mallory 9-60002
• Mercury 27-62386
• Mercury 27-62386001

Frequently Asked Questions

What engines does the Sierra 18-0182-9 thermostat gasket fit? It fits Johnson/Evinrude outboards rated at 200 HP built from 1977-83 and 235 HP built from 1978-85.

How many gaskets are in one package? The Sierra 18-0182-9 comes as a pack of 2 thermostat gaskets, giving you a spare or enough for a two-bank service job.

Is the Sierra 18-0182-9 interchangeable with other brands? Yes, it cross-references to GLM 30610, Evinrude/Johnson 310058, Mallory 9-60002, and Mercury 27-62386 / 27-62386001, so it can be ordered under any of those numbers.

What shape and color is this gasket? The 18-0182-9 gasket is round in shape with a multi-colored appearance.

How much does the Sierra 18-0182-9 pack weigh? The pack weighs 0.01 pounds.

Is this a genuine OEM part or an aftermarket replacement? The Sierra 18-0182-9 is an aftermarket thermostat gasket built to meet or exceed the quality of the original equipment part it replaces.

What is the UPC for the Sierra 18-0182-9 thermostat gasket? The UPC is 808282161484.

Does the Sierra 18-0182-9 work on a 225 HP Johnson/Evinrude outboard? No, the fitment for the 18-0182-9 covers 200 HP (1977-83) and 235 HP (1978-85) models; other horsepower and year ranges use a different Sierra thermostat gasket part number.

What comes in the box with this purchase? Each order includes 2 Sierra 18-0182-9 thermostat gaskets and nothing else.

Can the Mercury 27-62386 gasket be used in place of the Sierra 18-0182-9? Yes, Mercury 27-62386 (and 27-62386001) is one of the cross-reference numbers for the Sierra 18-0182-9, so either number will get you the same gasket.