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Sierra 18-3553 Thermostat for Johnson Evinrude Mercury Marine Outboard Engines

Manufacturer

Sierra

<h3>Sierra: Six Decades of Marine Aftermarket Excellence</h3><p><strong>Sierra</strong> has spent nearly 60 years earning its reputation as one of the most trusted names in the marine aftermarket industry. Originally focused on engine and drive components for boats, the brand has grown into a comprehensive source for nearly everything a boater needs to keep their vessel running at its best — from precision instrumentation to complete engine rebuild hardware.</p><p>Now operating as a brand of Dometic, Sierra manages global aftermarket distribution from a 300,000 sq. ft. facility in Litchfield, Illinois. The Sierra brand today encompasses not only its flagship marine parts line but also well-established marine names like Shields and Moeller, offering boaters a broader catalog than ever before. Whether you own an outboard, inboard, or sterndrive, Sierra's engineering team designs products to meet or exceed OEM specifications.</p><h3>Precision Instrumentation You Can Trust on the Water</h3><p>One of Sierra's most recognized product areas is its marine instrumentation lineup. The brand's <a href="/7570-sierra-gauge-set-1480">gauge sets</a> cover everything from classic analog instrument clusters to advanced digital multi-function displays. Sierra offers packages suited to outboards, sterndrives, and gasoline-powered inboards, with options ranging from coordinated analog kits in styles like Arctic, Eclipse, and Amega to modern touchscreen solutions like the R3 multi-function gauge. Features such as scratch-resistant domed glass lenses, silicone-dampened pointers, and perimeter backlighting make these instruments highly readable in all conditions.</p><p>Behind every accurate gauge reading is a properly calibrated sending circuit. Sierra's <a href="/7570-sierra-gauge-resistor-47908">gauge resistors</a> are a critical part of that chain, ensuring the signals from sensors and sending units are correctly interpreted by your instruments. These components are built to marine-grade standards to resist moisture, vibration, and corrosion — the realities of life on the water.</p><h3>Engine Internals Built to OEM Standards</h3><p>Sierra's history in marine power is perhaps best demonstrated by its deep catalog of engine components. The brand's <a href="/7570-sierra-engine-gasket-set-5404">engine gasket sets</a> cover a wide range of outboard and inboard applications and are engineered to deliver reliable seals in the demanding thermal and chemical environment of a marine engine. For boaters performing seasonal overhauls, top-end rebuilds, or full engine restorations, Sierra gasket kits are a go-to resource trusted by professional marine technicians and DIY boaters alike.</p><h3>A Complete Marine Parts Partner</h3><p>Beyond instrumentation and engine internals, Sierra's catalog spans fuel systems, electrical supplies, steering components, shore power, and more — all covered by what the brand calls an industry-leading warranty. Sierra also maintains a comprehensive parts-finder tool that enables cross-referencing with OEM part numbers from major manufacturers including Mercury, Yamaha, Suzuki, Volvo Penta, and others, making it straightforward to find the right replacement part for virtually any application.</p>

Part Number

18-3553
05/07/2036 10:45 AM
Sale Price

$18.63

In Stock (10+)

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Usually delivered within 2 days

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No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-3553 is a direct replacement thermostat designed for Johnson, Evinrude, and Mercury Marine outboard engines. This precision-engineered thermostat maintains optimal engine operating temperature by regulating coolant flow through the engine block.

Key Specifications:

  • Opening temperature: 143°F (61.7°C)
  • Direct OEM replacement quality
  • Corrosion-resistant construction for marine environments
  • Ensures proper engine temperature regulation

Maintaining the correct thermostat is essential for engine longevity and performance. A properly functioning thermostat prevents overheating while allowing the engine to reach optimal operating temperature quickly. Sierra Marine parts are manufactured to meet or exceed OEM specifications, providing reliable performance in demanding marine conditions.

Products specifications

Rating: Temperature

143°

Replaces

75692

It was good and my part arrived as promised

Very good

Very pleased will suggest your parts to everyone needing parts

easy to purchase.

No issues

thanks

Easy part search engine, easy order system and fast free delivery.

Great communication and fast shipping using FedEx Home. My packages can even be delivered on Saturday. Great prices on hard to find parts. I would definitely buy from again. Thanks

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Parts fit perfect and arrived quickly. Did not realize rubber grommet came in package of two so now I have spares. Thermostats came in individual packages so assumed grommets do to. Surprise! It's all good as price was right!

Parts fit perfect and arrived quickly. Did not realize rubber grommet came in package of two so now I have spares. Thermostats came in individual packages so assumed grommets do to. Surprise! It's all good as price was right!

Fast shipping and great prices. Amazon Payments was a breeze to use.

quick & easy

Very please with first buying experience with Autoplicity! Not only did they have the best price, I promptly received the following e-mail message the next day after I ordered.<br><br>Hello brian willard!, <br>Good news! You order has been shipped. <br>Order Number: 1412<br>Order Details: http://autoplicity.com/orderdetails.aspx?orderid=1412<br>Date Ordered: Wednesday, December 21, 2011<br>Tracking Number: 1Z4XR0770346534081

Everything was fine except I had an issue at the checkout. I tried to pay with my American Express but could not as there was an AVS mismatch, but it worked with my master card. I am in Australia and had the items sent to and American address so I would a

I was genuinely impressed with their price for my item and truly happy with the speed of their shipping. I'll definately look forward to buying from Autoplicity in the future!

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