Sierra Thermostat 18-3544, Replaces OEM 435491, for Evinrude and Johnson Outboards

The Sierra 18-3544 is a replacement thermostat engineered for Johnson and Evinrude outboard engines. It is a metal, temperature-regulating component that controls coolant flow through the engine's cooling system, helping the powerhead reach and hold proper operating temperature. As a direct replacement part, the Sierra 18-3544 is built to meet or exceed the performance of the original equipment thermostat it replaces.

This thermostat directly replaces OEM part number 435491 and is applicable across a range of Evinrude E-series and Johnson J-series outboard models and model years, as listed below. It ships as the thermostat component only.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3544
• Product Type: Thermostat
• Material: Metal
• Weight: 0.2 pounds
• UPC: 808282227555
• Replaces (OEM): 435491

Fitment

• Evinrude: E100 (2004-06), E110 (04-06), E115 (2002-06), E75 (2002-03), E90 (2002-03), E150 (1991-94), E175 (1991-94)
• Johnson: J105 (2003), J115 (2002-06), J150 (1991-92, 1993-94, 2002-06), J175 (1991-92, 1994, 2002-06), J90 (2004-06)

Replaces (OEM)

• 435491

Frequently Asked Questions

What OEM part number does the Sierra 18-3544 thermostat replace? The Sierra 18-3544 replaces OEM part number 435491.

Which outboard engines is the 18-3544 thermostat designed for? It is designed for Johnson and Evinrude outboard engines, including Evinrude E100, E110, E115, E75, E90, E150, and E175 models, and Johnson J105, J115, J150, J175, and J90 models.

Does the Sierra 18-3544 fit the Evinrude E175? Yes, the Sierra 18-3544 thermostat fits the Evinrude E175 for model years 1991-94.

Does the Sierra 18-3544 fit the Johnson J150? Yes, it fits the Johnson J150 for model years 1991-92, 1993-94, and 2002-06.

What is the Sierra 18-3544 thermostat made of? The 18-3544 thermostat is constructed of metal.

How much does the Sierra 18-3544 thermostat weigh? The Sierra 18-3544 thermostat weighs 0.2 pounds.

Is the Sierra 18-3544 a genuine Sierra part or an aftermarket equivalent? The 18-3544 is a genuine Sierra-branded replacement thermostat, built to meet or exceed the performance of the original OEM 435491 thermostat it replaces.

Does the Sierra 18-3544 come with a gasket? No, the 18-3544 includes only the thermostat itself; no gasket is included.

Is the Sierra 18-3544 the same as the Sierra 18-3546? No, the 18-3546 is a separate 130 degree F thermostat for different Evinrude and Johnson models (E200, E225, E250, J200, J225, J250) and is not interchangeable with the 18-3544.

What is the UPC for the Sierra 18-3544 thermostat? The UPC for the Sierra 18-3544 thermostat is 808282227555.

Will the 18-3544 work on both Johnson and Evinrude outboards? Yes, the Sierra 18-3544 is engineered to fit specific Johnson and Evinrude outboard models as listed in its fitment, since Johnson and Evinrude share compatible thermostat designs for these engines.

Does the Sierra 18-3544 fit the Evinrude E115? Yes, the 18-3544 fits the Evinrude E115 for model years 2002-06.