{"product_id":"sierra-18-3557-marine-thermostat-130f-replaces-evinrude-johnson-f335068-for-omc-outboard-cooling-systems","title":"Sierra 18-3557 143 Degree Marine Thermostat, White, Replaces Volvo Penta 21148403","description":"\u003cp\u003eThe Sierra 18-3557 is a 143 degree marine thermostat engineered to regulate engine coolant flow and keep your marine engine operating at the correct temperature range for efficient combustion and reduced wear. It is a white, plastic-bodied thermostat sized for direct fitment as a replacement engine cooling component, correcting overheating or slow-warm-up issues caused by a stuck, corroded, or failed factory thermostat. Installing a fresh thermostat is one of the most common and effective ways to restore proper engine temperature control and protect against overheating damage to gaskets, hoses, and engine internals.\u003c\/p\u003e\u003cp\u003eThe 18-3557 cross-references directly to Volvo Penta OE part number 21148403, giving boat owners and marine technicians a straightforward aftermarket alternative to the OEM part. It is sold as a standalone thermostat and is compatible with cooling systems designed around the referenced Volvo Penta OE number.\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 18-3557\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature Rating:\u003c\/strong\u003e 143 Degrees F\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Plastic\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.05 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999563019\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 21148403\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eVolvo Penta engines using OE part number 21148403\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e21148403\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat temperature rating is the Sierra 18-3557 thermostat?\u003c\/strong\u003e The Sierra 18-3557 is rated to open at 143 degrees Fahrenheit, which regulates when coolant begins circulating through the engine.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part does the Sierra 18-3557 replace?\u003c\/strong\u003e It replaces Volvo Penta OE part number 21148403, making it a direct cross-reference for that engine cooling application.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the Sierra 18-3557 made of?\u003c\/strong\u003e This thermostat has a white, plastic housing designed for durability in a marine engine cooling system.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-3557 thermostat weigh?\u003c\/strong\u003e The Sierra 18-3557 weighs 0.05 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-3557 a genuine Volvo Penta part or aftermarket?\u003c\/strong\u003e The 18-3557 is a Sierra-manufactured aftermarket thermostat built to replace Volvo Penta OE number 21148403, not a Volvo-branded part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat comes in the box with the 18-3557?\u003c\/strong\u003e The Sierra 18-3557 ships as a standalone thermostat unit.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use the 18-3557 as a routine maintenance replacement?\u003c\/strong\u003e Yes, replacing a thermostat like the Sierra 18-3557 on a routine or preventive basis, or at the first sign of overheating or slow warm-up, helps maintain proper engine temperature control.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the Sierra 18-3557 fit any thermostat housing?\u003c\/strong\u003e The 18-3557 is designed for engines that originally used Volvo Penta OE part 21148403; confirm your existing thermostat's part number matches before ordering.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the Sierra 18-3557 thermostat?\u003c\/strong\u003e It is white in color with a plastic body.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow do I know if my thermostat needs replacing?\u003c\/strong\u003e Symptoms like engine overheating, slow warm-up, or fluctuating temperature gauges often indicate a failed thermostat, and installing a Sierra 18-3557 is a common fix when your engine uses the 21148403 reference.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-3557 the same as other Sierra thermostats?\u003c\/strong\u003e No, the 18-3557 is a distinct Sierra part number specifically cross-referenced to Volvo Penta 21148403; other Sierra thermostat part numbers correspond to different OEM applications.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988153741531,"sku":"SIE-18-3557","price":28.53,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3557_lg__42732.1558126994.500.750.jpg?v=1785188005","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3557-marine-thermostat-130f-replaces-evinrude-johnson-f335068-for-omc-outboard-cooling-systems","provider":"Good Vibes Marina","version":"1.0","type":"link"}