{"product_id":"sierra-18-0844-thermostat-cover-gasket-replaces-yamaha-688-12414-a1-00-fits-yamaha-t60-t9-9-outboards","title":"Sierra Thermostat Cover Gasket 18-0844, Replaces Yamaha 688-12414-A1-00","description":"\u003cp\u003eThe Sierra 18-0844 is a thermostat cover gasket engineered to seal the thermostat housing on applicable Yamaha outboard engines. It forms the seal between the thermostat cover and the powerhead, preventing coolant leaks at this junction and ensuring the cooling system maintains proper pressure and flow around the thermostat. Sierra manufactures this gasket to meet or exceed the quality of the original equipment part it replaces, giving boat owners a reliable option when servicing the cooling system or replacing a worn or damaged gasket during a thermostat swap.\u003c\/p\u003e\u003cp\u003eThis gasket is a simple but essential wear item: over time, heat cycling and engine vibration can cause the original gasket material to harden, crack, or lose its seal, leading to coolant seepage around the thermostat cover. Replacing it whenever the thermostat cover is removed, such as during a thermostat replacement or cooling system inspection, is standard practice to avoid leaks after reassembly. The Sierra 18-0844 is sized and shaped to match the OEM thermostat cover gasket it replaces, so no modification is needed for installation.\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 18-0844\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Thermostat Cover Gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.01 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity:\u003c\/strong\u003e 1 gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999874771\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eYamaha outboard engines using thermostat cover OEM part 688-12414-A1-00\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e688-12414-A1-00\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-0844 gasket fit?\u003c\/strong\u003e The Sierra 18-0844 is a thermostat cover gasket for Yamaha outboard engines that use the OEM thermostat cover gasket 688-12414-A1-00.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-0844 the same as the Yamaha OEM gasket?\u003c\/strong\u003e Yes, the Sierra 18-0844 replaces Yamaha OEM part 688-12414-A1-00 and is built to meet or exceed the original equipment part's quality.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many gaskets are included with part 18-0844?\u003c\/strong\u003e One thermostat cover gasket is included per Sierra 18-0844 package.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the weight of the 18-0844 gasket?\u003c\/strong\u003e The 18-0844 thermostat cover gasket weighs 0.01 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhen should this gasket be replaced?\u003c\/strong\u003e Replace the 18-0844 gasket any time the thermostat cover is removed, such as during a thermostat inspection or replacement, since the old gasket material can lose its seal after being disturbed.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat happens if a worn thermostat cover gasket is not replaced?\u003c\/strong\u003e A worn or hardened thermostat cover gasket can allow coolant to leak at the thermostat housing, so installing a fresh 18-0844 gasket during service helps prevent seepage.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the Sierra 18-0844 include the thermostat itself?\u003c\/strong\u003e No, the 18-0844 is the cover gasket only; it does not include the thermostat.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material is the 18-0844 gasket made from?\u003c\/strong\u003e The 18-0844 thermostat cover gasket is made from OEM-equivalent gasket material to match the original Yamaha part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs Sierra 18-0844 genuine Yamaha or aftermarket?\u003c\/strong\u003e The 18-0844 is a Sierra-manufactured aftermarket gasket, made to meet or exceed the specifications of the original Yamaha equipment it replaces.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan the 18-0844 gasket be reused after removal?\u003c\/strong\u003e Thermostat cover gaskets like the 18-0844 are designed for one-time installation; once removed, the seal is generally compromised and a new gasket should be installed.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988085780699,"sku":"SIE-18-0844","price":4.16,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-0844_lg__45154.1558121240.500.750.jpg?v=1785188585","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-0844-thermostat-cover-gasket-replaces-yamaha-688-12414-a1-00-fits-yamaha-t60-t9-9-outboards","provider":"Good Vibes Marina","version":"1.0","type":"link"}