{"product_id":"merc-119","title":"Mercury MerCruiser - Heat Exchanger Kit 3.0L Side Mount MC-342 - 311342","description":"\u003cp\u003eThe MC-342 Fresh Water Closed Cooling Kit, part number 311342, is a half-system closed cooling conversion kit for MerCruiser 3.0L and 3.0LX GM 181 CID inline-4 marine engines. This kit converts the engine block from raw-water cooling to a closed-loop antifreeze\/coolant system, helping protect the block from internal salt, rust, scale, and corrosion buildup.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eKey Features\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eFresh water closed cooling conversion kit\u003c\/li\u003e\n\u003cli\u003eModel: MC-342\u003c\/li\u003e\n\u003cli\u003ePart number: 311342\u003c\/li\u003e\n\u003cli\u003eHalf-system design for engine block cooling\u003c\/li\u003e\n\u003cli\u003eSide-mount heat exchanger layout\u003c\/li\u003e\n\u003cli\u003eDesigned for MerCruiser 3.0L \/ 3.0LX GM 181 CID inline-4 engines\u003c\/li\u003e\n\u003cli\u003eCopper-alloy heat exchanger construction\u003c\/li\u003e\n\u003cli\u003eIncludes mounting hardware, hoses, clamps, thermostat housing spacer, and coolant recovery bottle\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cstrong\u003eEngine Compatibility\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eFits MerCruiser 3.0L and 3.0LX GM 181 CID inline-4 marine engines, commonly used in 1986–2002 applications.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eSerial Number Fitment Notice\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eVerify fitment by engine serial number, cooling-system layout, manifold\/riser configuration, and available engine-bay clearance before ordering. This is a half-system kit, so the engine block is converted to closed cooling while raw water continues to cool the exhaust manifold and riser.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eWhen This Part Needs Replacement\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eInstall this kit when converting a raw-water cooled MerCruiser 3.0L engine to closed cooling, especially for saltwater use or engines where long-term internal block corrosion protection is a priority.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eInstallation Notes\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThis side-mount kit is designed for tighter engine bays where a top-mount exchanger may not clear the hatch or deck. Installation typically includes mounting the exchanger to the side of the engine, routing molded coolant hoses, installing the thermostat housing spacer, adding the recovery bottle, and filling\/bleeding the closed cooling loop with the correct coolant mixture.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eAlternate\/Superseded Part Numbers\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eCommon references: MC-342 and 311342.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eParts Desk Insight\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eA half-system kit protects the engine block, but it does not convert the exhaust manifold and riser to closed cooling. Those components still see raw water, so they should remain on a normal inspection and replacement schedule.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eShipping:\u003c\/strong\u003e Locally warehoused, may take up to 3 days to ship. ⚓\u003c\/p\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":43563851186212,"sku":"311342","price":1645.82,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/1db3b4be-210c-45da-a4d6-1c377844e0f6_2c054439-8f63-4e66-b5e9-ff6a8d0ea8f1.png?v=1779392780","url":"https:\/\/marisolmarine.com\/products\/merc-119","provider":"Marisol Marine Company","version":"1.0","type":"link"}