{"product_id":"sierra-18-3251-water-pump-kit-impeller-wear-plate","title":"Sierra 18-3251 Water Pump Kit | Impeller, Wear Plate","description":"\u003cp class=\"nvn-hero\"\u003eThe Sierra 18-3251 Water Pump Kit gives you the three parts that actually wear out inside your engine's raw water pump: a fresh impeller, a new wear plate, and a new upper plate gasket. Refresh them on schedule and your engine keeps pushing a strong, steady stream of cooling water instead of gambling with an overheat.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eYour engine's raw water pump is the heart of its cooling system, and the impeller inside it is the one part guaranteed to wear out. The Sierra 18-3251 Water Pump Kit gives you the three components that take the beating: a fresh impeller, a new wear plate, and a new upper plate gasket. Refresh them on schedule and your engine keeps pulling a strong, steady stream of cooling water every time you run. Let them go too long, and you're gambling with an overheat that can cost you a powerhead.\u003c\/p\u003e\n\u003cp\u003eThis is a service kit, so it covers the parts that actually degrade. The impeller is the rubber vane wheel that moves water. Over a season of running it takes a set, the vanes stiffen, and the corners start to crack. The wear plate is the flat surface the impeller rides against inside the pump housing, and a scored or grooved plate will chew up a brand new impeller in short order. The upper plate gasket seals that plate so water goes where it should instead of leaking past. Replacing all three together is the right way to do the job once and do it right. Keep in mind this kit is the wear-parts refresh. If your pump also needs a new housing, cover, or the lower seals, those are separate items, so check what your particular pump calls for before you tear into it.\u003c\/p\u003e\n\u003cp\u003eA few things we've learned doing these. Note which way your impeller vanes curl before you pull the old one, because the new impeller has to bend the same direction the pump turns. Put it in backwards and it'll shred on the first start. Lube the new impeller with soapy water or a little glycerin, never petroleum grease, since petroleum swells the rubber and ruins it fast. Check that the wear plate sits perfectly flat with no warp. And when you close the pump back up, snug the cover screws down in a star pattern so the plate seats evenly and doesn't distort.\u003c\/p\u003e\n\u003cp\u003eOne more tip that saves grief later. Scrape every bit of the old upper plate gasket off the mating surfaces before you set the new one down. Old sealant or a torn scrap of the previous gasket is the number one reason a freshly serviced pump still weeps. Take a minute with a plastic scraper and get it clean. While you're in there, look over the pump housing itself for cracks or heavy pitting. This kit renews the wear items, but a housing that's damaged needs its own attention, and it's better to find that on the bench than at the ramp.\u003c\/p\u003e\n\u003cp\u003eWhen should you do this? Most of us pull the pump at least once a season, or roughly every hundred hours, whichever comes first. If you've run through sand or a muddy shallow, do it sooner, because grit is brutal on an impeller. And if your telltale stream has gone weak or you've seen the temp needle creep up, don't wait, that's the pump telling you it's tired. It's a couple hours of work on most outboards and sterndrives, and it's cheap insurance against a very expensive afternoon.\u003c\/p\u003e\n\u003cp\u003eSierra builds these to meet or exceed the original equipment part they replace, so you're not giving anything up by going with the kit instead of the dealer part. Match your engine's original water pump part number to the Sierra 18-3251 reference before you order, and you'll know it's the right fit. It's the kind of maintenance part every boater should keep a spare of on the shelf, because the day your impeller finally lets go is never a convenient one.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003eComplete water pump service kit with impeller, wear plate, and upper plate gasket in one box\u003c\/li\u003e\n  \u003cli\u003eNew impeller restores full, steady cooling water flow to protect against overheating\u003c\/li\u003e\n  \u003cli\u003eFresh wear plate gives the impeller a flat, unscored surface to ride against so it lasts\u003c\/li\u003e\n  \u003cli\u003eUpper plate gasket seals the pump plate to stop cooling water from leaking past\u003c\/li\u003e\n  \u003cli\u003eAll three high-wear parts renewed together for a do-it-once service\u003c\/li\u003e\n  \u003cli\u003eSierra parts meet or exceed the original equipment part they replace\u003c\/li\u003e\n  \u003cli\u003eCross-references to OEM part number 18-3251 for easy ordering\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's included in the Sierra 18-3251 kit?\u003c\/summary\u003e\n    \u003cp\u003eThree parts: the impeller, the wear plate, and the upper plate gasket. These are the components inside the water pump that wear out and need periodic replacement.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I replace my water pump impeller?\u003c\/summary\u003e\n    \u003cp\u003eMost boaters service the pump at least once a season, or roughly every 100 hours, whichever comes first. Do it sooner if you've run through sand or muddy shallows, since grit wears an impeller fast.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan I reuse my old wear plate?\u003c\/summary\u003e\n    \u003cp\u003eWe don't recommend it. If the old plate is scored or grooved it will chew up your new impeller quickly. The kit includes a fresh flat plate so the impeller has a clean surface to ride against.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat lubricant should I use on the new impeller?\u003c\/summary\u003e\n    \u003cp\u003eSoapy water or a little glycerin. Never use petroleum grease, because petroleum swells the neoprene vanes and ruins the impeller in short order.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes this kit include the pump housing or cover screws?\u003c\/summary\u003e\n    \u003cp\u003eNo. This is a wear-parts service kit covering the impeller, wear plate, and upper plate gasket. If your pump also needs a housing, cover, or lower seals, those are separate items.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes the impeller install direction matter?\u003c\/summary\u003e\n    \u003cp\u003eYes. The vanes have to bend the same direction the pump rotates. Note which way your old impeller's vanes curl before you pull it, because installing the new one backwards will shred it on the first start.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I know my impeller needs replacing?\u003c\/summary\u003e\n    \u003cp\u003eA weak or dribbling telltale stream, a temperature needle that creeps up, or vanes that are cracked, stiff, or have taken a permanent set are all signs it's time. When in doubt, replace it.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWill this fit my engine?\u003c\/summary\u003e\n    \u003cp\u003eMatch your engine's original water pump part number against the Sierra 18-3251 reference before ordering. Sierra designs these kits to meet or exceed the original equipment part they replace.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat happens if I run with a worn impeller?\u003c\/summary\u003e\n    \u003cp\u003eCooling water flow drops, the engine runs hot, and a serious overheat can damage the powerhead. A fresh impeller is cheap insurance against a very expensive repair.\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\u003eSierra 18-3251 Water Pump Kit\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\u003e18-3251\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e808282145552\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eWater Pump Kit\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eKit Contents\u003c\/th\u003e\n\u003ctd\u003eImpeller, Wear Plate, Upper Plate Gasket\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eImpeller\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eWear Plate\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUpper Plate Gasket\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSold As\u003c\/th\u003e\n\u003ctd\u003eComplete service kit\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eKeystone Part Number\u003c\/th\u003e\n\u003ctd\u003eS5M183251\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eReference Part Number\u003c\/th\u003e\n\u003ctd\u003e183251\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's included in the Sierra 18-3251 kit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Three parts: the impeller, the wear plate, and the upper plate gasket. These are the components inside the water pump that wear out and need periodic replacement.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How often should I replace my water pump impeller?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Most boaters service the pump at least once a season, or roughly every 100 hours, whichever comes first. Do it sooner if you've run through sand or muddy shallows, since grit wears an impeller fast.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Can I reuse my old wear plate?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"We don't recommend it. If the old plate is scored or grooved it will chew up your new impeller quickly. The kit includes a fresh flat plate so the impeller has a clean surface to ride against.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What lubricant should I use on the new impeller?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Soapy water or a little glycerin. Never use petroleum grease, because petroleum swells the neoprene vanes and ruins the impeller in short order.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does this kit include the pump housing or cover screws?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"No. This is a wear-parts service kit covering the impeller, wear plate, and upper plate gasket. If your pump also needs a housing, cover, or lower seals, those are separate items.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does the impeller install direction matter?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes. The vanes have to bend the same direction the pump rotates. Note which way your old impeller's vanes curl before you pull it, because installing the new one backwards will shred it on the first start.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How do I know my impeller needs replacing?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"A weak or dribbling telltale stream, a temperature needle that creeps up, or vanes that are cracked, stiff, or have taken a permanent set are all signs it's time. When in doubt, replace it.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Will this fit my engine?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Match your engine's original water pump part number against the Sierra 18-3251 reference before ordering. Sierra designs these kits to meet or exceed the original equipment part they replace.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What happens if I run with a worn impeller?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Cooling water flow drops, the engine runs hot, and a serious overheat can damage the powerhead. A fresh impeller is cheap insurance against a very expensive repair.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Sierra Marine","offers":[{"title":"Default Title","offer_id":45073299275869,"sku":"2009356","price":41.69,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_2520ee7b-c3a3-4402-a01c-ea8820743afa.jpg?v=1789766496","url":"https:\/\/nvnmarine.com\/products\/sierra-18-3251-water-pump-kit-impeller-wear-plate","provider":"NVN Marine","version":"1.0","type":"link"}