Description
Sierra 18-4456 marine exhaust protector valve. Compounded rubber flapper valves prevent water from entering the exhaust system. Made with weather resistant EPDM with U/V stabilizer. Includes: Stainless Steel Clamp, Size: 3″ or 76.2mm. Replaces: GLM 89240, Mallory 9-44000, Mercruiser Stern Drive 34765A2, 34765A1.
About SierraSierra provides premium-quality aftermarket replacements for over 6,000 marine parts, tools, and components. Sierra products are engineered to meet or exceed OEM standards, and stand up in harsh marine environments. Every new Sierra part comes with a limited lifetime warranty that covers the useful life of the product against any defects in workmanship and materials.
![Whitecap C.P. Brass Sillcock 1-5/8″ Base 3-3/16 Depth[P-2452C]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/whitecap-c-p-brass-sillcock-1-5-8-base-3-3-16-depth-p-2452c.webp)
![Rapala Combo Pack – Pliers, Clipper, PunchSharpener [RTC-6PCHS]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/rapala-combo-pack-pliers-clipper-punchsharpener-rtc-6pchs.webp)
![GROCO 1-1/4″ Bronze Electric Flanged Seacock – 12V [FBVE-1250 12V]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/groco-1-1-4-bronze-electric-flanged-seacock-12v-fbve-1250-12v.webp)
![Scanpod Helm Pod System – White[SPH-SYSTEM-W]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/scanpod-helm-pod-system-white-sph-system-w.webp)
![Blue Sea 7605 BatteryLink Charger – 10Amp – 2-Bank[7605]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/blue-sea-7605-batterylink-charger-10amp-2-bank-7605.webp)
![Xantrex Conext Combox Communication Box f/Freedom SW Series Inverters/Chargers[809-0918]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/xantrex-conext-combox-communication-box-f-freedom-sw-series-inverters-chargers-8.webp)
![Dometic 25 Insulated Flex R4.2 Ducting/Duct – 4″ [9108549910]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/dometic-25-insulated-flex-r4-2-ducting-duct-4-9108549910.webp)
![SmartPlug 50 Amp 50 Dual Configuration Cordset w/Marina Park Power End [C50504]](https://www.durablemarinebattery.com/wp-content/uploads/2026/08/smartplug-50-amp-50-dual-configuration-cordset-w-marina-park-power-end-c50504.webp)