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Sierra 18-3569 Marine Engine Thermostat Kit

Manufacturer

Sierra

<p>For nearly six decades, Sierra has established itself as one of the marine industry's most trusted names in aftermarket engine and drive parts. Founded as a specialized marine parts manufacturer, Sierra has grown into a comprehensive supplier of replacement components, instrumentation, and accessories for both recreational and commercial boating applications. Operating from their 300,000-square-foot distribution center in Litchfield, Illinois, Sierra serves boat owners and marine technicians worldwide with an extensive catalog of parts engineered specifically for the harsh saltwater environment.</p><h3>Marine Engine Excellence</h3><p>Sierra's reputation was built on delivering precision-engineered internal engine components and drive system parts that meet or exceed OEM specifications. Their <a href="/7570-sierra-engine-gasket-set-5404">engine gasket sets</a> provide critical sealing solutions for inboard and outboard motors, while their <a href="/7570-sierra-engine-complete-assembly-15341">engine complete assemblies</a> offer comprehensive replacement options for major overhauls. Each component undergoes rigorous testing to ensure reliability in demanding marine conditions, from corrosion resistance to temperature cycling performance.</p><h3>Instrumentation and Monitoring Systems</h3><p>Accurate instrumentation is essential for boat operators to monitor engine health and prevent costly breakdowns on the water. Sierra's comprehensive line of <a href="/7570-sierra-gauges-200483">gauges</a> includes everything from fuel pressure and temperature indicators to voltmeters and trim gauges, all designed with marine-grade materials that withstand vibration, moisture, and UV exposure. Their <a href="/7570-sierra-tachometer-gauge-1488">tachometer gauges</a> deliver precise RPM readings critical for optimizing engine performance and fuel efficiency. Supporting these instruments, Sierra's <a href="/7570-sierra-gauge-resistor-47908">gauge resistors</a> ensure proper signal conditioning and accurate readings across various sensor types and engine configurations.</p><h3>Expanded Product Portfolio</h3><p>In 2022, Sierra significantly broadened its scope beyond traditional marine engine parts to encompass a wider range of boating accessories and even outdoor power equipment components. This strategic expansion brought established marine brands like Shields and Moeller under the Sierra umbrella, creating a one-stop resource for marine maintenance and replacement parts. The company now offers fuel systems, electrical components, battery charging solutions, and NMEA electronics alongside their traditional engine parts lineup.</p><h3>Quality Backed by Industry-Leading Warranties</h3><p>What sets Sierra apart in the crowded aftermarket marine parts market is their commitment to standing behind every component they manufacture. Their warranty coverage extends beyond simple part replacement—it includes shop labor, haul-out fees, towing charges, and related incidental costs should a warrantied part fail. This comprehensive protection reflects the company's confidence in their manufacturing processes and quality control standards. For boat owners facing repairs far from shore or mechanics working on customer vessels, this peace of mind is invaluable. Whether you're maintaining an outboard motor, rebuilding an inboard engine, or upgrading your boat's instrumentation, Sierra's decades of marine industry experience and commitment to quality make them a reliable choice for keeping your vessel running at peak performance.</p>

Part Number

118-3569
05/28/2036 5:50 AM
Sale Price

$20.83

3 left at this price

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Usually delivered within 2 days

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No Hassle Returns

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Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-3569 Thermostat Kit is engineered specifically for Mercury and Mariner 2-stroke outboard motors ranging from 70 to 125 HP (1987 and newer models). This complete replacement kit ensures your outboard engine operates at optimal temperature for maximum performance and efficiency.

Complete Kit Includes:

  • 18-3549 Thermostat (120°F/49°C temperature rating)
  • 18-0182 Thermostat Gasket
  • 18-0339 Thermostat Cover Gasket

Key Features:

  • Meets or exceeds OEM specifications for reliable performance
  • Direct replacement for Mercury Marine part number 803061T1
  • Compatible with multiple engine models: 70, 75, 80, 90 HP (3-cylinder) and 100, 115, 125 HP (4-cylinder)
  • All components included for complete installation—no need to source individual parts
  • Also replaces GLM 13124, Mallory 9-43155, and Pro Marine 8032

A properly functioning thermostat is essential for maintaining the correct operating temperature in your outboard motor. Running outside the optimal temperature range can lead to reduced performance, decreased fuel efficiency, and potential engine damage. Sierra Marine products are designed to restore function to OEM specifications, ensuring your engine runs at peak performance.

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