{"product_id":"sierra-5w-30-full-synthetic-marine-oil-5-quart-jug","title":"Sierra 5W-30 Full Synthetic Marine Oil, 5 Quart Jug","description":"\u003cp class=\"nvn-hero\"\u003eSierra's full synthetic 5W-30 is marine oil built for turbocharged inboards, not repackaged automotive stock. The 5-quart jug carries the NMMA FC-W CAT rating, so it's safe for engines with catalytic exhaust and formulated to fight the heat, moisture, and corrosion that come with life on the water. One jug, one clean oil change.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eIf you run a turbocharged inboard, you already know the oil takes a beating. Turbos spin up hot, the bilge stays damp, and the engine sits for weeks between runs. Sierra's full synthetic 5W-30 is built for exactly that kind of life. It's a marine-grade oil, not automotive stock poured into a different jug, and it carries the NMMA FC-W CAT rating that gas inboard and sterndrive engines are spec'd for.\u003c\/p\u003e\n\u003cp\u003eThe 5W-30 grade does two jobs. The 5W side flows fast on a cold start, so the moment you crank a cold engine on a spring morning the oil is already climbing to the top end instead of draining back to the pan. The 30 side holds its film once everything's up to temperature and the turbo is loading the bearings hard. Full synthetic base stock is what lets it do both. It resists thinning out when things get hot and it doesn't wax up when the boat's been sitting in a cold slip.\u003c\/p\u003e\n\u003cp\u003eThat FC-W CAT rating matters more than it looks. FC-W is the marine four-stroke standard, and the CAT part means the oil is catalyst compatible. If your engine has a catalytic exhaust system, and most modern gas inboards do, a low-phosphorus catalyst-safe oil keeps the converter from getting poisoned over time. Pour in the wrong automotive oil and you can quietly kill an expensive part. This one's formulated to protect it.\u003c\/p\u003e\n\u003cp\u003eMarine oil also has to fight things car oil never sees. Humidity, condensation in the crankcase, salt in the air. Sierra builds in corrosion and rust protection so the internals stay clean while the boat's parked, which is most of the time for most of us. The additive package is aimed at holding off varnish and sludge through the long idle periods and the short, hot runs that are normal on the water.\u003c\/p\u003e\n\u003cp\u003eSo who's this for? Owners running turbocharged gas inboards and sterndrives that call for a 5W-30 full synthetic marine oil. Check your engine manual for the exact grade and the FC-W requirement before you pour. It's not the oil for a carbureted low-output block that specs a heavier straight-weight, and it's not a two-stroke or a diesel oil. When in doubt, match what the engine builder calls out.\u003c\/p\u003e\n\u003cp\u003eThe jug is five quarts, a single container. A lot of smaller four and six cylinder inboards take right around five quarts with a filter change, so one jug often does a complete service. Bigger V8s and some turbo sixes hold more, so grab a second jug if your capacity runs over five. Always fill to the dipstick, not to the jug. And pair it with a fresh spin-on filter that matches your engine's mount so you're not chasing a leak after the first run.\u003c\/p\u003e\n\u003cp\u003eOn change intervals, follow your engine manual first. A hard-run turbo motor lives a hotter life than a mild inboard, so a lot of owners tighten the interval up and change oil more often on boats that see heavy load or high coolant temps. Pull the dipstick, look at the oil, and don't stretch it just to save a jug. Synthetic buys you margin, not permission to skip a change.\u003c\/p\u003e\n\u003cp\u003eStorage-wise, this is where a good synthetic earns its keep. Change the oil before winter layup, not after. Fresh oil with a clean additive package sits in the engine over the off-season without the acids and moisture that used oil carries, so you're not letting your bearings soak in contaminated oil for five months. Come spring, it's ready to go.\u003c\/p\u003e\n\u003cp\u003eBottom line, it's a straightforward, marine-correct oil for turbo inboards from a name that's supplied marine engine parts for decades. Buy the right grade, use a matching filter, fill to the dipstick, and change it on schedule. That's the whole game with engine oil, and this jug covers the oil half of it properly.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003eFull synthetic 5W-30 base stock, flows fast on cold starts and holds its film when the turbo loads the bearings hot\u003c\/li\u003e\n  \u003cli\u003eNMMA FC-W CAT rated, catalyst compatible so it won't poison the converter on catalyst-equipped gas inboards\u003c\/li\u003e\n  \u003cli\u003e5-quart jug (single), enough for a complete oil change on many four and six cylinder inboards\u003c\/li\u003e\n  \u003cli\u003eMarine-specific corrosion and rust inhibitors, protect the internals through long idle periods and damp bilges\u003c\/li\u003e\n  \u003cli\u003eFormulated for turbocharged inboard and sterndrive gasoline engines that call for 5W-30 synthetic\u003c\/li\u003e\n  \u003cli\u003eAnti-varnish and anti-sludge additive package, keeps the engine clean through short hot runs and seasonal layup\u003c\/li\u003e\n  \u003cli\u003eSierra Marine 18-9558CAT-4, engineered to meet or exceed the OEM marine oil it replaces\u003c\/li\u003e\n  \u003cli\u003eSAE 5W-30 multigrade, one oil for cold-slip mornings and full-throttle summer runs\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Sierra Marine reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat does the FC-W CAT rating mean?\u003c\/summary\u003e\n    \u003cp\u003eFC-W is the NMMA standard for four-stroke marine engine oil, and CAT means it's catalyst compatible. If your gas inboard has a catalytic exhaust system, this low-phosphorus formula protects the converter that automotive oils can damage.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhich 5W-30 is best for a turbocharged inboard?\u003c\/summary\u003e\n    \u003cp\u003eA full synthetic marine 5W-30 that carries the FC-W CAT rating, like this Sierra jug. Synthetic handles turbo heat better than conventional, and the marine spec adds the corrosion protection a boat engine needs. Always confirm the grade in your engine manual.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs there a difference between 5W-30 and SAE 5W-30?\u003c\/summary\u003e\n    \u003cp\u003eNo. SAE just refers to the Society of Automotive Engineers, the body that sets the viscosity grades. SAE 5W-30 and 5W-30 are the same viscosity.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWill one 5-quart jug do a full oil change?\u003c\/summary\u003e\n    \u003cp\u003eOften yes. A lot of four and six cylinder inboards take right around five quarts with a filter change. Larger V8s and some turbo sixes hold more, so check your engine's capacity and grab a second jug if it runs over five. Fill to the dipstick, not to the jug.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan I use this in a carbureted or non-turbo engine?\u003c\/summary\u003e\n    \u003cp\u003eOnly if your engine manual calls for a 5W-30 full synthetic FC-W oil. Some older carbureted blocks spec a heavier grade. Match what the engine builder specifies rather than assuming.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I change it?\u003c\/summary\u003e\n    \u003cp\u003eFollow your engine manual for the hour interval. Hard-run turbo motors live hotter, so many owners change more often on boats that see heavy load or high coolant temps. Synthetic gives you margin, but don't stretch a change just to save a jug.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs full synthetic worth it over conventional for a boat?\u003c\/summary\u003e\n    \u003cp\u003eFor a turbo inboard, yes. Synthetic resists thermal breakdown under turbo heat and stays fluid on cold starts, and it holds its additive package longer through the idle and layup cycles that are normal on the water.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eShould I change the oil before winter storage?\u003c\/summary\u003e\n    \u003cp\u003eYes, change it before layup, not after. Fresh oil keeps acids and moisture out of the engine over the off-season, so the bearings aren't soaking in contaminated oil for months. It's ready to run in spring.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat oil filter should I use with it?\u003c\/summary\u003e\n    \u003cp\u003eUse a spin-on filter that matches your engine's mount and the manufacturer's spec. A correct filter seals properly and keeps you from chasing a leak after the first run.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eSAE 5W-30 Full Synthetic, 5 Quart Jug, Single, For Turbo Inboards\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eSierra Marine\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e18-9558CAT-4\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e808282390082\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eOil Type\u003c\/th\u003e\n\u003ctd\u003eFull Synthetic\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSAE Viscosity Grade\u003c\/th\u003e\n\u003ctd\u003e5W-30\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eMarine Specification\u003c\/th\u003e\n\u003ctd\u003eNMMA FC-W CAT (Catalyst Compatible)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCatalyst Compatible\u003c\/th\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eContainer Size\u003c\/th\u003e\n\u003ctd\u003e5 Quarts\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eContainer Type\u003c\/th\u003e\n\u003ctd\u003eJug\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePackage Quantity\u003c\/th\u003e\n\u003ctd\u003eSingle (1 Jug)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eEngine Application\u003c\/th\u003e\n\u003ctd\u003eTurbocharged Inboard Gasoline Engines\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What does the FC-W CAT rating mean?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"FC-W is the NMMA standard for four-stroke marine engine oil, and CAT means it's catalyst compatible. If your gas inboard has a catalytic exhaust system, this low-phosphorus formula protects the converter that automotive oils can damage.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Which 5W-30 is best for a turbocharged inboard?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"A full synthetic marine 5W-30 that carries the FC-W CAT rating, like this Sierra jug. Synthetic handles turbo heat better than conventional, and the marine spec adds the corrosion protection a boat engine needs. Always confirm the grade in your engine manual.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is there a difference between 5W-30 and SAE 5W-30?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"No. SAE just refers to the Society of Automotive Engineers, the body that sets the viscosity grades. SAE 5W-30 and 5W-30 are the same viscosity.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Will one 5-quart jug do a full oil change?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Often yes. A lot of four and six cylinder inboards take right around five quarts with a filter change. Larger V8s and some turbo sixes hold more, so check your engine's capacity and grab a second jug if it runs over five. Fill to the dipstick, not to the jug.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Can I use this in a carbureted or non-turbo engine?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Only if your engine manual calls for a 5W-30 full synthetic FC-W oil. Some older carbureted blocks spec a heavier grade. Match what the engine builder specifies rather than assuming.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How often should I change it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Follow your engine manual for the hour interval. Hard-run turbo motors live hotter, so many owners change more often on boats that see heavy load or high coolant temps. Synthetic gives you margin, but don't stretch a change just to save a jug.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is full synthetic worth it over conventional for a boat?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"For a turbo inboard, yes. Synthetic resists thermal breakdown under turbo heat and stays fluid on cold starts, and it holds its additive package longer through the idle and layup cycles that are normal on the water.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Should I change the oil before winter storage?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes, change it before layup, not after. Fresh oil keeps acids and moisture out of the engine over the off-season, so the bearings aren't soaking in contaminated oil for months. It's ready to run in spring.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What oil filter should I use with it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Use a spin-on filter that matches your engine's mount and the manufacturer's spec. A correct filter seals properly and keeps you from chasing a leak after the first run.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Sierra Marine","offers":[{"title":"Default Title","offer_id":45068924584029,"sku":"2009038","price":55.69,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_70a385a6-4951-4f99-be19-4f3605d68096.png?v=1789689386","url":"https:\/\/nvnmarine.com\/products\/sierra-5w-30-full-synthetic-marine-oil-5-quart-jug","provider":"NVN Marine","version":"1.0","type":"link"}