Sierra 18-3013 Upper Water Pump Seal for Mercury/Mariner Outboard Motors

Sierra

<h3>About Sierra Marine Parts</h3><p>With more than 58 years of experience in the marine aftermarket industry, <strong>Sierra</strong> has earned its reputation as one of the most trusted names in boat engine components and marine supplies worldwide. From weekend anglers to commercial vessel operators, boaters rely on Sierra for dependable, precision-engineered parts that keep engines running at their best — whether they're heading out on a freshwater lake or battling open-ocean conditions.</p><p>Sierra's extensive catalog covers virtually every aspect of marine engine maintenance and repair. The brand is perhaps best known for its industry-leading line of <a href="/7570-sierra-gauges-200483">marine gauges</a>, offering accurate, durable instrumentation for monitoring critical engine parameters like speed, fuel level, oil pressure, and water temperature. Reliable gauges are the eyes of any vessel's helm, and Sierra's instruments are engineered to perform in the demanding marine environment where moisture, vibration, and saltwater exposure are constant challenges.</p><p>Keeping a marine engine healthy starts with proper lubrication, and Sierra's <a href="/7570-sierra-engine-oil-12138">marine engine oil</a> is formulated specifically for the unique demands of inboard and outboard powerplants. Marine engines operate under load profiles and cooling conditions very different from automotive applications, making purpose-built marine oil an essential part of any maintenance routine.</p><p>Sierra's breadth of <a href="/7570-sierra-engine-parts-accessories-200373">engine parts and accessories</a> makes it a go-to source for mechanics and DIY boaters alike. From water pumps and thermostats to belts, filters, and ignition components, Sierra produces OEM-quality replacements designed to fit a wide range of popular marine engine brands — helping boaters avoid costly dealer markups without sacrificing reliability.</p><p>One of the more specialized areas of Sierra's catalog is its lineup of <a href="/200133-manifoldsriserselbows-sierra-7570">manifolds, risers, and elbows</a> — critical exhaust cooling components on sterndrive and inboard engines. These parts are subjected to extreme heat and constant water flow, making quality and correct fitment absolutely essential for safe operation. Sierra manufactures these components to exacting standards to help prevent the kind of catastrophic failures that can result from worn or corroded exhaust hardware.</p><p>Rounding out Sierra's core fuel system offerings is a comprehensive selection of <a href="/7570-sierra-fuel-pumps-201310">marine fuel pumps</a>, designed to deliver consistent, reliable fuel delivery across a wide range of inboard and outboard applications. A failing fuel pump can leave a boat stranded far from shore, making preventive replacement with a quality Sierra component a smart choice for any boater.</p><p>In 2022, the Sierra brand expanded its footprint even further, incorporating well-established marine lines such as Shields and Moeller into a comprehensive aftermarket boating portfolio. Today, Sierra continues to innovate and grow its catalog, serving both marine and land-based applications with the same commitment to quality that has defined the brand for nearly six decades.</p>