{"product_id":"sierra-18-3650-thermostat-kit-for-mercruiser-replaces-mercury-59078t3-includes-thermostat-gasket","title":"Sierra 18-3650 Complete Thermostat Housing Kit, Replaces 3377341, for MerCruiser 120\/140 153\/181 CID L4 Engines","description":"\u003cp\u003eThe Sierra 18-3650 is a complete thermostat housing kit engineered as a direct replacement for MerCruiser 120 and 140 model sterndrive engines built around the 153 and 181 cubic inch L4 blocks. Rather than a bare thermostat, this is a full housing kit, meaning the components needed to replace a worn or corroded thermostat housing assembly are included in one part number, simplifying the repair instead of requiring multiple separate purchases. It is intended for engines within the 1968-1989 production span covered by the applicable MerCruiser 120\/140 L4 engine families, including the later 2.5L 153 cid L4 variant.\u003c\/p\u003e\u003cp\u003eThis kit directly replaces the OEM thermostat housing components originally used across several engine year ranges, and cross-references to numerous factory MerCruiser part numbers so it can be identified and ordered using either the Sierra number or the original equipment number. For the 1968-1972 120\/153 L4 application, the kit corresponds to engines fitted with a cast iron exhaust manifold. Installation follows standard thermostat housing service: drain the cooling system, remove the old housing and thermostat, install the new gasket and housing from the kit, and refill and bleed the cooling system per the engine service manual.\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 18-3650\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Complete thermostat housing kit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Mercruiser Thermostats \u0026amp; Gaskets\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.13 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999236920\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross-Reference:\u003c\/strong\u003e 2324347, 3377340, 3377341, B531853, B531854, C853255, 2508261, B450800\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMerCruiser 120, 153 cid L4, 1968-1972 (cast iron exhaust manifold engines)\u003c\/li\u003e\n\u003cli\u003eMerCruiser 120, 153 cid L4, 1972-1986\u003c\/li\u003e\n\u003cli\u003eMerCruiser 2.5L, 153 cid L4, 1987-1989\u003c\/li\u003e\n\u003cli\u003eMerCruiser 140, 181 cid L4, 1968-1986\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e2324347\u003c\/li\u003e\n\u003cli\u003e3377340\u003c\/li\u003e\n\u003cli\u003e3377341\u003c\/li\u003e\n\u003cli\u003eB531853\u003c\/li\u003e\n\u003cli\u003eB531854\u003c\/li\u003e\n\u003cli\u003eC853255\u003c\/li\u003e\n\u003cli\u003e2508261\u003c\/li\u003e\n\u003cli\u003eB450800\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-3650 kit include?\u003c\/strong\u003e The Sierra 18-3650 is a complete thermostat housing kit, meaning it supplies the housing assembly components needed to replace a worn or leaking factory thermostat housing in a single part number rather than requiring separate individual pieces.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhich engines does the 18-3650 thermostat housing kit fit?\u003c\/strong\u003e It fits MerCruiser 120 and 140 sterndrive engines built on the 153 cid and 181 cid L4 blocks, covering the 1968-1972, 1972-1986, and 1968-1986 model ranges depending on engine variant, as well as the 2.5L 153 cid L4 engine used from 1987-1989.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-3650 kit work on the 1968-1972 MerCruiser 120?\u003c\/strong\u003e Yes, for the 1968-1972 MerCruiser 120 with the 153 cid L4 engine, the 18-3650 kit applies to engines fitted with a cast iron exhaust manifold.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part numbers does the Sierra 18-3650 replace?\u003c\/strong\u003e The 18-3650 cross-references to OEM numbers 2324347, 3377340, 3377341, B531853, B531854, C853255, 2508261, and B450800, covering the various MerCruiser 120\/140 L4 engine years it fits.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-3650 the same part as the Sierra 18-3551?\u003c\/strong\u003e No. The 18-3551 is a separate Sierra part number used for the MerCruiser 140 six-cylinder application, while 18-3650 is the complete housing kit for the 120\/140 L4 (153\/181 cid) applications listed.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-3650 thermostat kit weigh?\u003c\/strong\u003e The Sierra 18-3650 thermostat housing kit weighs 0.13 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this kit fit a 2.5L MerCruiser engine?\u003c\/strong\u003e Yes, the 18-3650 kit fits the MerCruiser 2.5L 153 cid L4 engine for the 1987-1989 model years.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I identify this part by its UPC?\u003c\/strong\u003e Yes, the Sierra 18-3650 thermostat housing kit carries UPC 030999236920.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-3650 an aftermarket or genuine OEM part?\u003c\/strong\u003e The 18-3650 is a Sierra-branded replacement kit designed to be a direct equivalent for the original MerCruiser thermostat housing components it cross-references, rather than a factory MerCruiser-branded part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the difference between the 120 and 140 applications for this kit?\u003c\/strong\u003e Both the MerCruiser 120 (153 cid L4) and 140 (181 cid L4) engines use the Sierra 18-3650 kit, but each engine family has its own set of OEM cross-reference numbers listed for the specific model years it covers.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988156756187,"sku":"SIE-18-3650","price":28.85,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3650_lg__55891.1558126614.500.750.jpg?v=1785188149","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3650-thermostat-kit-for-mercruiser-replaces-mercury-59078t3-includes-thermostat-gasket","provider":"Good Vibes Marina","version":"1.0","type":"link"}