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Sierra 118-3550 Marine Thermostat 140 Degree for MerCruiser

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

118-3550
05/28/2036 5:53 AM
Sale Price

$22.53

2 left at this price

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Usually delivered within 2 days

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Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 118-3550 is a premium marine thermostat designed for MerCruiser stern drives and select Chrysler/Force/US Marine engines. Engineered to meet or exceed OEM specifications, this thermostat features a 140-degree Fahrenheit temperature rating and is constructed from durable copper and brass materials to withstand harsh marine environments.

Key Features:

  • 140°F opening temperature rating for optimal engine cooling performance
  • Copper and brass construction for corrosion resistance and reliability
  • Direct replacement for Mercury/MerCruiser and Chrysler/Force applications
  • Designed specifically for raw water cooled marine engines
  • Meets or exceeds original equipment manufacturer standards

Application:

  • MerCruiser 120/2.5L (s/n 2324347 & up) with cast iron exhaust manifolds
  • MerCruiser 140-3.0L (s/n 0L340999 & below)
  • MerCruiser 165 GM 250 I/L6 engines
  • Various MerCruiser 2.5L and 3.0L GM engines from 1982-1998

OEM Cross-References: Replaces Mercury/MerCruiser 59078, 59078A1, 59078B; Chrysler/Force/US Marine F84068, F84068-1, F84068-2, F85068-2; GLM 13020; and Mallory 9-43020. This ensures proper fit and function across multiple marine engine platforms.

Backed by Sierra's industry-leading warranty, this thermostat is designed to provide reliable temperature regulation for the useful life of the product. Sierra has been a trusted name in marine replacement parts for over 50 years, delivering high-quality components engineered to meet today's demanding marine applications.

Thank you for a quick and east purchase

Great website and easy to find what I was looking for. Prices were very competitive also.

Great product and price. Customer service and communication above and beyond. Highly recommend.

Would have gotten 5 stars but product info was not stated correctly.

Excellent product and service.

Super fast shipping!

Would buy again

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