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Sierra 18-4458 Exhaust Flapper Valve 5-6 Inch Marine

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

18-4458
06/01/2036 1:47 AM
Sale Price

$78.70

In Stock (10+)

delivery box

Usually delivered within 2 days

free shipping

FREE SHIPPING

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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 18-4458 is a weather-resistant rubber exhaust flapper valve designed for marine applications with 5 to 6 inch exhaust systems. This replacement flapper prevents water from entering the exhaust system when the engine is off, protecting your engine from potential damage.

Key Features:

  • Weather-resistant rubber construction for durability in harsh marine environments
  • Fits 5 to 6 inch diameter exhaust hoses
  • Includes stainless steel hose clamp for secure installation
  • One-way valve design prevents water backflow into exhaust system
  • Direct replacement for worn or damaged exhaust flappers

This exhaust flapper valve is an essential component for maintaining your marine engine's integrity by creating a barrier against water intrusion while allowing exhaust gases to escape freely during operation.

Products specifications

Size

5" & 6"

Very content, look to shop again if need arises.

What I needed, shipping fees are higher than I expected.

A

A+

On time... and exactly what I ordered, I would recommend it to anyone

Happy

N/A

I just got it. Not sure about the rest. Thank you

Quick and easy

Great prices. Fast shipping. Huge inventory.

Search to ID the right part looks good so I bought. Sure hope it fits!

Fast and hopefully easy

Best price for a superior product and no gimmickry or BS about the product.

very fast processing received product within a few days. fair prices. will do business with again.

fast

Couldn't use paypal but other than that it was fine. Battery came with a broken top, packaging was not up to the std. of other Optima batteries I have ordered on line.

Excellent website, good price, fast shipping anda pleasure to do business with.

Found good price and reasonable shipping. Thanks. H

fast transaction

Fast shipping and saved $60 on a $399 item. However you have to verify your part #'s with the vendor. The part discription on autoplicity sometimes is not what you get. I ordered an item that said it was an O2 plug and bung but when it showed up it was just the bung plug sold separate and customer service basically said it was my bad for not checking for a more accurate discription on the Allstar web site.

Recently ordered a cargo liner and I must say, Autoplicity had the cheapest price anywhere! Excellent communication and super fast shipping! Will definitely do business with Autoplicity again! Thank you for a wonderful shopping experience!

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