{"product_id":"exhaust-flapper-protector-valve-fits-mercruiser-chrysler-crusader-pleasurecraft-replaces-sierra-18-4458-mallory-9-44002-glm-89260-volvo-penta-834438-4","title":"Exhaust Flapper Protector Valve – Fits MerCruiser, Chrysler, Crusader, Pleasurecraft (Replaces Sierra 18-4458, Mallory 9-44002, GLM 89260, Volvo Penta 834438-4)","description":"\u003csection\u003e\n\u003c!-- 🔧 Table Styles (include only once per page) --\u003e\n\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eExhaust Flapper Protector Valve – Fits Marine Stern Drives \u0026amp; Inboards 5\" \u0026amp; 6\"\u003c\/strong\u003e is designed for a wide range of marine stern drives and inboard engines with 5-inch and 6-inch exhaust outlets, including models from MerCruiser, Chrysler, Crusader, and Pleasurecraft (PCM).\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct replacement for several common part numbers, including Sierra 18-4458, Mallory 9-44002, GLM 89260, and Volvo Penta 834438-4.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eExternal mount on the exhaust outlet for straightforward installation.\u003c\/li\u003e\n\u003cli\u003eMade with weather-resistant EPDM rubber with a UV stabilizer for durability in marine environments.\u003c\/li\u003e\n\u003cli\u003eIncludes a stainless steel clamp for a secure and corrosion-resistant connection.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-4458\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMallory\u003c\/td\u003e\n        \u003ctd\u003e9-44002\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGLM\u003c\/td\u003e\n        \u003ctd\u003e89260\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eVolvo Penta\u003c\/td\u003e\n        \u003ctd\u003e834438-4\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n\u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cp\u003eCompatible with various inboard and sterndrive engines from Chris-Craft, Chrysler, Crusader, Pleasurecraft (PCM), and Mercury\/Mariner that use a 5\" or 6\" exhaust flapper.\u003c\/p\u003e\n\u003cp\u003eAlso fits specific Volvo Penta applications calling for OEM part number 834438-4.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eModel\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eChris-Craft\u003c\/td\u003e\n        \u003ctd\u003eInboard\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eChrysler\u003c\/td\u003e\n        \u003ctd\u003eInboard\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCrusader\u003c\/td\u003e\n        \u003ctd\u003eInboard\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003ePleasurecraft (PCM)\u003c\/td\u003e\n        \u003ctd\u003eWaukesha\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eInboard\/Outboard\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eVolvo Penta\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e834438-4\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eExhaust Flapper Protector Valve\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eExternal mount on exhaust outlet\u003c\/dd\u003e\n  \u003cdt\u003eConnection\u003c\/dt\u003e\n\u003cdd\u003eHose barb with included clamp\u003c\/dd\u003e\n  \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eCR Rubber, Stainless Steel\u003c\/dd\u003e\n  \u003cdt\u003eHousing Color\u003c\/dt\u003e\n\u003cdd\u003eBlack\u003c\/dd\u003e\n  \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e5\" \u0026amp; 6\" (127mm \u0026amp; 152.4mm) diameter\u003c\/dd\u003e\n  \u003cdt\u003eWeight\u003c\/dt\u003e\n\u003cdd\u003e0.422 kg (14.9 oz)\u003c\/dd\u003e\n  \u003cdt\u003eFitting Type\u003c\/dt\u003e\n\u003cdd\u003eBarb\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eMade with weather-resistant EPDM with UV stabilizer; 5\" installation requires two 45° cuts\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 x Exhaust Protector Valve (18-4458)\u003c\/li\u003e\n  \u003cli\u003e1 x \u003cspan style=\"color:#d0021b;\"\u003eStainless Steel Clamp (6-1\/16\" to 7\")\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eEnsure the engine is off and has cooled completely before beginning work.\u003c\/li\u003e\n  \u003cli\u003eLocate and access the exhaust outlet where the old flapper is located.\u003c\/li\u003e\n  \u003cli\u003eFor installation on a \u003cstrong\u003e5-inch outlet\u003c\/strong\u003e, you must make two 45° cuts on the valve's housing to ensure a proper fit. No cuts are necessary for 6-inch outlets.\u003c\/li\u003e\n  \u003cli\u003eSlide the new protector valve fully onto the exhaust outlet.\u003c\/li\u003e\n  \u003cli\u003ePosition the new stainless steel clamp over the hose barb section of the valve.\u003c\/li\u003e\n  \u003cli\u003eTighten the clamp securely until the valve is held firmly in place, preventing any potential exhaust or water leaks.\u003c\/li\u003e\n  \u003cli\u003eStart the engine briefly to check for proper operation and ensure there are no exhaust leaks around the new seal.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I know if this flapper valve will fit my engine?\u003c\/summary\u003e\n  \u003cp\u003eThis valve is designed for 5\" and 6\" exhaust outlets on various stern drive and inboard engines, including MerCruiser, Chrysler, and Crusader. The best way to confirm fitment is to measure your exhaust outlet diameter and compare your old part number to the cross-references: Sierra 18-4458, Mallory 9-44002, GLM 89260, or Volvo Penta 834438-4.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the purpose of the cuts required for a 5\" installation?\u003c\/summary\u003e\n  \u003cp\u003eThe valve is designed to be compatible with both 5\" and 6\" outlets. For the smaller 5\" diameter, making two 45° cuts allows the flexible rubber to conform correctly and create a tight, secure seal without bunching up or causing a leak.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs that my old exhaust flapper is failing?\u003c\/summary\u003e\n  \u003cp\u003eCommon symptoms of a worn or failed flapper include a distinct rattling or clacking noise from the exhaust at idle, visible cracks or missing pieces of rubber on the valve, and in severe cases, water being forced back into the engine (water ingestion).\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should this part be replaced?\u003c\/summary\u003e\n  \u003cp\u003eReplacement intervals depend on usage (freshwater vs. saltwater) and exposure to sun and weather. It is best practice to inspect the flapper annually for signs of cracking, brittleness, or tearing and consider replacing it every few seasons as part of your preventative maintenance schedule.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this an OEM or aftermarket part?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. All our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow much is shipping and how fast is it?\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free to most regions, and expedited options will appear at checkout if they are available for your location.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is your warranty and return policy?\u003c\/summary\u003e\n  \u003cp\u003eThis part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window, provided the part is unused and in its original condition. See our full policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement part, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or quality control.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50717900669243,"sku":"KF23EF445","price":45.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/KF23EF445.png?v=1762937868","url":"https:\/\/seasierra.com\/products\/exhaust-flapper-protector-valve-fits-mercruiser-chrysler-crusader-pleasurecraft-replaces-sierra-18-4458-mallory-9-44002-glm-89260-volvo-penta-834438-4","provider":"SeaSierra","version":"1.0","type":"link"}