{"product_id":"sierra-18-1989-thermostat-housing-stainless-steel-replaces-mercruiser-8m0061381-fits-mercruiser-gm-v-8-454-502-cid-7-4l-8-2l","title":"Sierra Thermostat Housing 18-1989, Replaces Mercruiser 8M0061381 861006A1, Fits GM V-8 454\/502 MCM\/MIE","description":"\u003cp\u003eThe Sierra 18-1989 Thermostat Housing is a stainless steel replacement housing built for MCM\/MIE GM V-8 (454 \u0026amp; 502 cid) marine engines. Stainless steel construction resists corrosion in salt and fresh water environments while providing long service life under sustained engine heat and vibration. This housing is manufactured to meet or exceed OEM specifications, giving boat owners a direct, reliable replacement for a worn, cracked, or leaking factory thermostat housing.\u003c\/p\u003e\u003cp\u003eA properly sealed thermostat housing is essential for maintaining correct engine operating temperature, which affects performance improvement and throttle response. The 18-1989 is designed as a direct fit for the applications listed below, and Sierra offers the 18-1989K Thermostat Service Kit as the matching source for the gasket, thermostat, and other service parts needed when installing this housing.\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 18-1989\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Thermostat Housing\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Stainless Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 3.9 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e MCM\/MIE GM V-8 (454 \u0026amp; 502 cid) engines\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eService Kit:\u003c\/strong\u003e 18-1989K Thermostat Service Kit (for replacement parts)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eMCM\/MIE GM V-8 (454 \u0026amp; 502 cid) engines\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMercruiser 8M0061381\u003c\/li\u003e\n\u003cli\u003eMercruiser 861006A1\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-1989 Thermostat Housing fit?\u003c\/strong\u003e The Sierra 18-1989 Thermostat Housing fits MCM\/MIE GM V-8 (454 \u0026amp; 502 cid) marine engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part numbers does the 18-1989 replace?\u003c\/strong\u003e This housing replaces Mercruiser 8M0061381 and Mercruiser 861006A1, so either OEM number can be used to confirm a correct match to the Sierra 18-1989.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material is the Sierra 18-1989 Thermostat Housing made of?\u003c\/strong\u003e It is made of stainless steel, chosen for corrosion resistance in marine engine cooling systems exposed to salt and fresh water.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-1989 Thermostat Housing weigh?\u003c\/strong\u003e The Sierra 18-1989 Thermostat Housing weighs 3.9 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-1989 come with a thermostat and gasket?\u003c\/strong\u003e No, the 18-1989 is the housing itself; the matching 18-1989K Thermostat Service Kit provides the replacement parts such as the thermostat and gasket needed for installation.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-1989 a genuine OEM part or aftermarket?\u003c\/strong\u003e The 18-1989 is a Sierra-manufactured aftermarket housing engineered to meet or exceed OEM specifications for Mercruiser 8M0061381 and 861006A1 applications.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy does a marine engine thermostat housing need to be stainless steel?\u003c\/strong\u003e Stainless steel construction on the Sierra 18-1989 resists the corrosion that raw water cooling systems cause in marine engines, extending service life compared to housings made from less resistant materials.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat should I order along with the 18-1989 housing for a full replacement?\u003c\/strong\u003e Sierra recommends the 18-1989K Thermostat Service Kit alongside the 18-1989 housing for the replacement parts needed to complete the installation.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the 18-1989 improve engine performance?\u003c\/strong\u003e A correctly sealed and functioning thermostat housing like the Sierra 18-1989 supports proper engine operating temperature, which contributes to performance improvement and throttle response.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-1989 housing specific to one engine cid, or does it cover multiple sizes?\u003c\/strong\u003e The Sierra 18-1989 is designed for MCM\/MIE GM V-8 engines in both 454 and 502 cid configurations.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988090040539,"sku":"SIE-18-1989","price":251.28,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/xa__61079.1753840676.500.750.jpg?v=1785188531","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-1989-thermostat-housing-stainless-steel-replaces-mercruiser-8m0061381-fits-mercruiser-gm-v-8-454-502-cid-7-4l-8-2l","provider":"Good Vibes Marina","version":"1.0","type":"link"}