{"product_id":"sierra-18-15121-serpentine-belt-replaces-mercruiser-57-865615005-57-863876-5-87-5-in-x-13-16-in","title":"Sierra Serpentine Belt 18-15121 for MerCruiser MX 6.2L MPI MIE, Horizon, Ski Engines","description":"\u003cp\u003eThe Sierra 18-15121 serpentine belt is a direct-fit drive belt engineered for MerCruiser MX 6.2L MPI engines, including MIE, Horizon MIE, and Ski configurations within the applicable serial number ranges. It is built to OEM quality standards for correct fit, form, and function, so it drives the alternator, water pump, and other belt-driven accessories exactly as the original equipment belt did.\u003c\/p\u003e\u003cp\u003eConstruction uses high quality polychloroprene rubber combined with polyester fiber tensile members, giving the belt oil resistance and temperature stability for continuous duty in a marine engine compartment. The serpentine mount design routes a single belt around multiple pulleys, and the belt is finished in white.\u003c\/p\u003e\u003cp\u003eThis belt is intended for MerCruiser MX 6.2L MPI Horizon MIE and MX 6.2L MPI MIE engines with serial number OM310100 and up on engines with standard cooling, and for MerCruiser MX 6.2L MPI Ski engines with serial number OM317000 and up. Confirm your engine's serial number and cooling configuration before ordering, since MerCruiser used different belt part numbers across serial breaks and cooling types.\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 18-15121\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Polyester, Rubber\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBelt Style:\u003c\/strong\u003e Serpentine Mount\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.52 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282200442\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCountry of Origin:\u003c\/strong\u003e United States\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 57-865615005\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitment:\u003c\/strong\u003e MerCruiser MX 6.2L MPI (MIE, Horizon MIE, Ski)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMerCruiser MX 6.2L MPI Horizon MIE, 2001-05, serial OM310100 and up, engines with standard cooling\u003c\/li\u003e\n\u003cli\u003eMerCruiser MX 6.2L MPI MIE, 2001-05, serial OM310100 and up, engines with standard cooling\u003c\/li\u003e\n\u003cli\u003eMerCruiser MX 6.2L MPI Ski, 2002-05, serial OM317000 and up\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e57-865615005\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-15121 serpentine belt fit?\u003c\/strong\u003e This belt fits MerCruiser MX 6.2L MPI Horizon MIE and MX 6.2L MPI MIE engines from 2001-05 with serial number OM310100 and up on engines with standard cooling, and MerCruiser MX 6.2L MPI Ski engines from 2002-05 with serial number OM317000 and up.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the serial number of my engine matter when ordering this belt?\u003c\/strong\u003e Yes, serial number matters because MerCruiser MX 6.2L MPI engines switched belt part numbers at certain serial breaks. The 18-15121 belt covers OM310100 and up (MIE and Horizon MIE, standard cooling) and OM317000 and up (Ski), so confirm your engine's serial number before ordering.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part number does 18-15121 replace?\u003c\/strong\u003e Sierra 18-15121 replaces OEM number 57-865615005, so it is a direct cross-reference for engines that originally used that MerCruiser belt.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the 18-15121 belt made of?\u003c\/strong\u003e The belt is constructed with polychloroprene rubber and polyester fiber tensile members, giving it oil resistance and temperature stability for marine engine use.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-15121 serpentine belt weigh?\u003c\/strong\u003e The 18-15121 serpentine belt weighs 0.52 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this belt a genuine Sierra part or a generic aftermarket belt?\u003c\/strong\u003e Sierra 18-15121 is a Sierra-branded aftermarket belt built to OEM quality standards for correct fit, form, and function, rather than a generic universal belt.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this belt work on an engine with closed cooling?\u003c\/strong\u003e The 18-15121 belt is specified for MerCruiser MX 6.2L MPI MIE and Horizon MIE engines with standard cooling; MerCruiser used a different Sierra belt part number for the closed cooling versions of these engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the difference between 18-15121 and 18-15122?\u003c\/strong\u003e 18-15121 covers MerCruiser MX 6.2L MPI engines with serial OM310100 and up on standard cooling (MIE, Horizon MIE) plus Ski engines with serial OM317000 and up, while 18-15122 is the corresponding Sierra belt for the same engine families on closed cooling with serial OM317000 and up.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included when I order this belt?\u003c\/strong\u003e Each order includes one Sierra 18-15121 serpentine belt; no additional pulleys, tensioners, or hardware are included.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-15121 a serpentine or V-belt design?\u003c\/strong\u003e It is a serpentine mount belt, meaning a single ribbed belt routes around multiple pulleys rather than using separate individual V-belts.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the Sierra 18-15121 belt?\u003c\/strong\u003e The 18-15121 serpentine belt is white.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhere is the Sierra 18-15121 belt manufactured?\u003c\/strong\u003e The 18-15121 serpentine belt's country of origin is the United States.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988088336603,"sku":"SIE-18-15121","price":86.29,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-15121_lg__23772.1722487821.500.750.jpg?v=1785189020","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-15121-serpentine-belt-replaces-mercruiser-57-865615005-57-863876-5-87-5-in-x-13-16-in","provider":"Good Vibes Marina","version":"1.0","type":"link"}