{"product_id":"sierra-18-0398-9-thermostat-gasket-replaces-mercruiser-27-33918-27-8m2021920-for-mercruiser-volvo-penta-pack-of-2","title":"Sierra 18-0398-9 Thermostat Gasket, Pack of 2, Replaces Mercruiser 27-33918 and OMC 385211","description":"\u003cp\u003eThe Sierra 18-0398-9 thermostat gasket seals the thermostat housing on compatible marine engines, providing a leak-free seal between the housing and the engine block or manifold. Sold in a pack of two, it gives boat owners and technicians enough material on hand to complete a full thermostat service or to keep a spare for the next maintenance interval. The gasket is manufactured by Sierra to meet or exceed the quality of the original equipment part it replaces, making it a straightforward drop-in during a thermostat replacement, cooling system inspection, or general engine maintenance.\u003c\/p\u003e\u003cp\u003eBecause thermostat housings and gaskets are shared across several engine brands, the 18-0398-9 cross-references to a range of OEM part numbers from Mercruiser, OMC, Volvo Penta, GLM, and Mallory, so it can be ordered using whichever number appears on the old gasket or in the engine's parts manual. Its light weight and simple flat-gasket design make it easy to install with basic hand tools once the old thermostat and gasket are removed and the mating surfaces are cleaned.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-0398-9\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Thermostat Gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePackage Quantity:\u003c\/strong\u003e Pack of 2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.01 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282161569\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cp\u003eFits engines that use a thermostat housing gasket cross-referenced to the Mercruiser, OMC, Volvo Penta, GLM, and Mallory part numbers listed below.\u003c\/p\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eGLM 35060\u003c\/li\u003e\n\u003cli\u003eMallory 9-60009\u003c\/li\u003e\n\u003cli\u003eMercruiser 27-33918\u003c\/li\u003e\n\u003cli\u003eMercruiser 27-8M2021920\u003c\/li\u003e\n\u003cli\u003eOMC 385211\u003c\/li\u003e\n\u003cli\u003eOMC 312797\u003c\/li\u003e\n\u003cli\u003eVolvo Penta 835417\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-0398-9 thermostat gasket cross-reference to?\u003c\/strong\u003e The Sierra 18-0398-9 thermostat gasket is interchangeable with GLM 35060, Mallory 9-60009, Mercruiser 27-33918, Mercruiser 27-8M2021920, OMC 385211, OMC 312797, and Volvo Penta 835417.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many gaskets come with an order of 18-0398-9?\u003c\/strong\u003e This listing for the Sierra 18-0398-9 thermostat gasket is priced and sold as a pack of two gaskets.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-0398-9 gasket meet original equipment quality?\u003c\/strong\u003e Yes, the Sierra 18-0398-9 thermostat gasket is manufactured to meet or exceed the quality of the original equipment part it replaces.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this gasket fit a Mercruiser engine thermostat housing?\u003c\/strong\u003e Yes, the Sierra 18-0398-9 gasket cross-references to Mercruiser part numbers 27-33918 and 27-8M2021920.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-0398-9 gasket compatible with OMC engines?\u003c\/strong\u003e Yes, it cross-references to OMC part numbers 385211 and 312797.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the Sierra 18-0398-9 gasket work on Volvo Penta engines?\u003c\/strong\u003e Yes, the Sierra 18-0398-9 thermostat gasket cross-references to Volvo Penta part number 835417.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-0398-9 thermostat gasket weigh?\u003c\/strong\u003e The Sierra 18-0398-9 thermostat gasket weighs 0.01 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat UPC is used for the Sierra 18-0398-9 gasket?\u003c\/strong\u003e The Sierra 18-0398-9 thermostat gasket is identified by UPC 808282161569.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow do I confirm 18-0398-9 is the correct gasket for my engine?\u003c\/strong\u003e Match the part number stamped on your old thermostat gasket, or your engine's parts manual, against the cross-reference numbers for the Sierra 18-0398-9: GLM 35060, Mallory 9-60009, Mercruiser 27-33918, Mercruiser 27-8M2021920, OMC 385211, OMC 312797, or Volvo Penta 835417.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this a genuine Sierra part or a generic aftermarket copy?\u003c\/strong\u003e The 18-0398-9 is manufactured and sold under the Sierra brand, part number 18-0398-9, rather than an unbranded generic part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included when I purchase the 18-0398-9 gasket?\u003c\/strong\u003e An order of Sierra 18-0398-9 includes two thermostat gaskets, sold as a pack.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan the 18-0398-9 gasket be used with a Mallory or GLM thermostat housing?\u003c\/strong\u003e Yes, the Sierra 18-0398-9 thermostat gasket cross-references to GLM 35060 and Mallory 9-60009.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988073132251,"sku":"SIE-18-0398-9","price":5.7,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-0398-9__19628.1737854133.500.750.jpg?v=1785188003","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-0398-9-thermostat-gasket-replaces-mercruiser-27-33918-27-8m2021920-for-mercruiser-volvo-penta-pack-of-2","provider":"Good Vibes Marina","version":"1.0","type":"link"}