{"product_id":"sierra-18-0389-heat-exchanger-end-gasket-replaces-mercruiser-27-99960-3-15-16-in-mercruiser-cooling-system","title":"Sierra 18-0389 Heat Exchanger End Gasket, Replaces 27-75450, 224 CID, 2-3\/4 Inch Diameter","description":"\u003cp\u003eThe Sierra 18-0389 Heat Exchanger End Gasket seals the end cover of the heat exchanger on 224 CID marine engines, forming the barrier between the raw water and coolant sides of the cooling system. It is built as a direct cross-reference replacement for OEM number 27-75450, giving boat owners and marine technicians a reliable option for cooling system service and rebuilds without waiting on OEM parts. The gasket measures 2-3\/4 inches in diameter, sized to match the heat exchanger end cover it is designed for.\u003c\/p\u003e\u003cp\u003eThis gasket is a wear item that should be replaced any time the heat exchanger end cap is removed for inspection, descaling, or cleaning, since a used gasket will not reliably reseal and can allow coolant or raw water leakage. Installing a fresh gasket at each service interval helps maintain proper sealing pressure across the heat exchanger end cover and supports consistent engine cooling performance. As part of the Mercruiser cooling system parts group, it is intended for use during routine heat exchanger maintenance and cooling system rebuilds.\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 18-0389\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Heat Exchanger End Gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDiameter:\u003c\/strong\u003e 2-3\/4 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine Displacement:\u003c\/strong\u003e 224 CID\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 27-75450\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShape:\u003c\/strong\u003e Round\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e Multicoloured\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999873705\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePackage Quantity:\u003c\/strong\u003e 1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.08 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cp\u003eDesigned for 224 CID marine engines using a heat exchanger cooling system.\u003c\/p\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e27-75450\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-0389 Heat Exchanger End Gasket fit?\u003c\/strong\u003e The Sierra 18-0389 is designed for 224 CID marine engines that use a heat exchanger cooling system, sealing the heat exchanger end cover.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part number does the 18-0389 gasket replace?\u003c\/strong\u003e It replaces OEM number 27-75450, making it a direct cross-reference for that original part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the diameter of this gasket?\u003c\/strong\u003e The Sierra 18-0389 Heat Exchanger End Gasket measures 2-3\/4 inches in diameter.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many gaskets come in one package?\u003c\/strong\u003e Each package of the 18-0389 contains a package quantity of 1 gasket.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-0389 gasket weigh?\u003c\/strong\u003e It weighs 0.08 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhen should this heat exchanger end gasket be replaced?\u003c\/strong\u003e Replace the 18-0389 gasket any time the heat exchanger end cover is removed for cleaning, descaling, or inspection, since a reused gasket will not reseal reliably.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-0389 an OEM part or an aftermarket replacement?\u003c\/strong\u003e The 18-0389 is a Sierra aftermarket gasket manufactured as a cross-reference replacement for OEM part 27-75450, not an OEM-branded part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat happens if this gasket is not replaced during heat exchanger service?\u003c\/strong\u003e Reinstalling an old, compressed gasket on the heat exchanger end cover of a 224 CID engine can lead to coolant or raw water leaks at the end cover seam.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat shape and color is the 18-0389 gasket?\u003c\/strong\u003e The Sierra 18-0389 is a round gasket with a multicoloured appearance.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-0389 gasket suitable for a cooling system rebuild?\u003c\/strong\u003e Yes, it is intended for use in heat exchanger maintenance and cooling system rebuilds on 224 CID marine engines.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988073099483,"sku":"SIE-18-0389","price":8.92,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-0389_lg__31448.1558120273.500.750.jpg?v=1785188573","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-0389-heat-exchanger-end-gasket-replaces-mercruiser-27-99960-3-15-16-in-mercruiser-cooling-system","provider":"Good Vibes Marina","version":"1.0","type":"link"}