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Sierra 118-3531 Thermostat Housing for MerCruiser Stern Drives

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

118-3531
07/13/2036 3:01 PM
Sale Price

$15.22

1 left at this price

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Usually delivered within 2 days

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Fitment guaranteed

Product Details

The Sierra 118-3531 (also referenced as 18-3531) is a replacement thermostat housing designed specifically for MerCruiser stern drive engines with closed cooling systems. This housing replacement kit fits V6 and V8 MerCruisers, compatible with MCM/MCI GM V6 and V8 (305, 350, 454, and 502 cu. in.) based marine engines with closed cooling systems.

Key Features:

  • Engineered to match OEM housings to ensure the fit and function will be to factory specifications
  • Includes the necessary seal to complete the installation
  • Mating surfaces have been CNC machined to eliminate additional preparation
  • Durable construction with non-corrosive, hard-wearing parts and components
  • Manufactured to meet or exceed OEM requirements

OEM Cross-Reference:

  • Mercury Marine 861188A1
  • GLM 13540
  • Mallory 9-42501

The engine's cooling system components take a beating - constantly heat cycled and exposed to salt water and fresh water, these parts corrode at a much faster rate than other engine parts. The Sierra 118-3531 provides a reliable, out-of-the-box solution for damaged or corroded thermostat housings in your MerCruiser cooling system.

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