{"product_id":"sierra-18-0612-marine-oil-pan-for-mercruiser-gm-small-block-v8-replaces-809910-14259-1-piece-rear-main-seal-rh-dipstick","title":"Sierra Rear Main Seal 18-0612 - Replaces Mercruiser 809910, 14259 - GM Small Block V8","description":"\u003cp\u003eThe Sierra 18-0612 is a one-piece rear main seal engineered for GM Small Block V8 engines built with a right-handed dipstick, as used in Mercruiser sterndrive applications. This seal fits between the engine block and the crankshaft flange at the rear of the engine, sealing the crankshaft bore to keep engine oil from leaking past the crankcase. Sierra manufactures the 18-0612 to OEM interchange standards so it installs as a direct equivalent without requiring modification, cross-referencing to Mercruiser OEM numbers 809910 and 14259.\u003c\/p\u003e\u003cp\u003eThe 18-0612 is one of several rear main seals in Sierra's lineup, each matched to a specific engine family and dipstick orientation. Because the correct seal depends on whether the block is GM Small Block, Big Block, or V6, and whether the dipstick is left- or right-handed, ordering the exact part number for your engine is important to get a proper seal. The 18-0612 is specifically the one-piece design for GM Small Block V8 engines with a right-handed dipstick.\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 18-0612\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Rear Main Seal\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeal Type:\u003c\/strong\u003e 1-Piece\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine Compatibility:\u003c\/strong\u003e GM Small Block V8 (Right Handed Dipstick)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 809910, 14259\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 7.48 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eMercruiser sterndrive engines: GM Small Block V8 (Right Handed Dipstick)\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e809910\u003c\/li\u003e\n\u003cli\u003e14259\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-0612 rear main seal fit?\u003c\/strong\u003e The 18-0612 is a one-piece rear main seal built for GM Small Block V8 engines with a right-handed dipstick, as used in Mercruiser sterndrive applications.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-0612 a one-piece or two-piece seal?\u003c\/strong\u003e One piece. The 18-0612 uses a single-piece rear main seal design, while Sierra's 18-0613 is the two-piece version built for the same GM Small Block V8 engine.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhich OEM numbers does the 18-0612 replace?\u003c\/strong\u003e It replaces Mercruiser OEM numbers 809910 and 14259.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the 18-0612 fit a GM Big Block V8?\u003c\/strong\u003e No. Big block V8 applications use Sierra 18-0614 (one-piece) or 18-0615 (two-piece); the 18-0612 is built specifically for GM Small Block V8 engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy does the dipstick side matter for this seal?\u003c\/strong\u003e GM Small Block V8 engines are produced in both left- and right-handed dipstick configurations, and the 18-0612 is engineered for the right-handed dipstick version, so it must be matched to that configuration to seal properly.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-0612 weigh?\u003c\/strong\u003e The Sierra 18-0612 rear main seal weighs 7.48 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this a genuine Sierra part or an aftermarket copy?\u003c\/strong\u003e The 18-0612 is manufactured by Sierra to OEM specifications as a direct replacement for Mercruiser 809910 and 14259.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included when I order the 18-0612?\u003c\/strong\u003e Each order of the 18-0612 includes one rear main seal unit.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-0612 work on a GM V6 engine?\u003c\/strong\u003e No. GM V6 engines use the separate Sierra 18-0616 rear main seal; the 18-0612 is designed only for GM Small Block V8 engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat Mercruiser engines use the 18-0612 seal?\u003c\/strong\u003e Mercruiser GM Small Block V8 engines with a right-handed dipstick use the 18-0612, which cross-references to OEM 809910 and 14259.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow is the 18-0612 different from the 18-0614?\u003c\/strong\u003e The 18-0612 is the one-piece rear main seal for GM Small Block V8 engines, while the 18-0614 is the corresponding one-piece seal for GM Big Block V8 engines; the two are not interchangeable.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-0612 sold as a single seal?\u003c\/strong\u003e Yes, the Sierra 18-0612 rear main seal ships as a single unit weighing 7.48 pounds.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988084338907,"sku":"SIE-18-0612","price":356.61,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/18-0612___20184.1753840673.500.750.jpg?v=1785188140","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-0612-marine-oil-pan-for-mercruiser-gm-small-block-v8-replaces-809910-14259-1-piece-rear-main-seal-rh-dipstick","provider":"Good Vibes Marina","version":"1.0","type":"link"}