{"product_id":"thermostat-housing-kit-fits-mercury-mariner-verado-135-400-hp-replaces-892864t04-8m0174561","title":"Thermostat Housing Kit – Fits Mercury\/Mariner Verado 135-400 HP (Replaces 892864T04, 8M0174561)","description":"\u003csection\u003e\n\u003c!-- 🔧 Table Styles (include only once per page) --\u003e\n\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eThermostat Housing Kit – Fits Mercury\/Mariner Verado 135-400 HP (Replaces 892864T04, 8M0174561)\u003c\/strong\u003e is engineered for Mercury and Mariner Verado four-stroke outboard engines from 135 HP to 400 HP (2004–present). It ensures your engine maintains optimal operating temperature by precisely regulating coolant flow for peak performance and longevity.\u003c\/p\u003e\n\u003cp\u003eThis assembly is a direct replacement for Mercury part numbers 892864T04 and 8M0174561, as well as Sierra equivalents 18-3631 and 18-3631-K.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eEngineered for direct OEM replacement, ensuring a perfect fit and function.\u003c\/li\u003e\n  \u003cli\u003eIncludes the thermostat pre-seated within the housing for a simplified installation.\u003c\/li\u003e\n  \u003cli\u003eComes complete with the necessary O-ring seal to prevent coolant leaks.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n        \u003cth\u003eSuperseded By\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e892864T04\u003c\/td\u003e\n        \u003ctd\u003e8M0174561\u003c\/td\u003e\n        \u003ctd\u003eOriginal OEM part number.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e8M0174561\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003eCurrent OEM part number.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3631\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003eAftermarket cross-reference.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3631-K\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003eAftermarket kit version.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n\u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cp\u003eThis part is designed specifically for the Mercury and Mariner Verado L4 and L6 engine platforms. Please verify your serial number against the notes provided in the table to ensure correct fitment.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eModel\u003c\/th\u003e\n        \u003cth\u003eRated HP\u003c\/th\u003e\n        \u003cth\u003eStroke\u003c\/th\u003e\n        \u003cth\u003eYears\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L4\u003c\/td\u003e\n        \u003ctd\u003e135\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e4-cylinder models (1B227000-2B576734)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L4\u003c\/td\u003e\n        \u003ctd\u003e150\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e4-cylinder models (1B227000-2B576734)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L4\u003c\/td\u003e\n        \u003ctd\u003e175\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e4-cylinder models (1B227000-2B576734)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L4\u003c\/td\u003e\n        \u003ctd\u003e200\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e4-cylinder models (1B517159-2B576734)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6\u003c\/td\u003e\n        \u003ctd\u003e200\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e6-cylinder models (0T980000-2B578935)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6 Pro\u003c\/td\u003e\n        \u003ctd\u003e200\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003ePro 6-cylinder models (2B034840-2B577715)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6\u003c\/td\u003e\n        \u003ctd\u003e225\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e6-cylinder models (0T980000-2B578935)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6\u003c\/td\u003e\n        \u003ctd\u003e250\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e6-cylinder models (0T980000-2B578935)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6 Pro\u003c\/td\u003e\n        \u003ctd\u003e250\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003ePro 6-cylinder models (1B830170-2B577715)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6\u003c\/td\u003e\n        \u003ctd\u003e275\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e6-cylinder models (0T980000-2B578935)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6\u003c\/td\u003e\n        \u003ctd\u003e300\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e6-cylinder models (1B517434-2B578935)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6 Pro\u003c\/td\u003e\n        \u003ctd\u003e300\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2004–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003ePro 6-cylinder models (1B830170-2B577715)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6 Pro\u003c\/td\u003e\n        \u003ctd\u003e350\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2015–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e2.6L L6 Pro models (2B141124-3B342962)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6\u003c\/td\u003e\n        \u003ctd\u003e350\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2015–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e2.6L L6 models (2B141617-3B342962)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eVerado L6\u003c\/td\u003e\n        \u003ctd\u003e400\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2016–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e2.6L L6 models (2B618256-3B342962)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003eRacing L6\u003c\/td\u003e\n        \u003ctd\u003e400R\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2015–Present\u003c\/td\u003e\n        \u003ctd\u003e892864T04\/8M0174561\u003c\/td\u003e\n        \u003ctd\u003e2.6L L6 Racing models (2B141124-3B342962)\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eThermostat Housing Assembly\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect OEM Replacement\u003c\/dd\u003e\n  \u003cdt\u003eConnection\u003c\/dt\u003e\n\u003cdd\u003eHose connection with clamp\u003c\/dd\u003e\n  \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eComposite (OEM) or Metal Alloy (Aftermarket)\u003c\/dd\u003e\n  \u003cdt\u003eOperating Temperature\u003c\/dt\u003e\n\u003cdd\u003e140°F (60°C) nominal opening temperature\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eIncludes thermostat pre-seated in housing, O-ring seal required for installation\u003c\/dd\u003e\n  \u003cdt\u003eWarranty\u003c\/dt\u003e\n\u003cdd\u003e1-year manufacturer warranty (varies by brand)\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 x Thermostat with Housing Assembly (Replaces 892864T04\/8M0174561)\u003c\/li\u003e\n  \u003cli\u003e\u003cspan style=\"color:#d0021b;\"\u003e1 x O-Ring Seal (8M005958)\u003c\/span\u003e\u003c\/li\u003e\n  \u003cli\u003e1 x Clamp (888988008) (Note: Included with some kits, but may require separate purchase)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eEnsure the engine is off and completely cool. Disconnect the negative battery terminal.\u003c\/li\u003e\n  \u003cli\u003ePlace a drain pan under the engine and carefully drain the coolant from the system.\u003c\/li\u003e\n  \u003cli\u003eLocate the thermostat housing and disconnect the attached coolant hoses.\u003c\/li\u003e\n  \u003cli\u003eRemove the mounting bolts securing the old housing assembly and carefully lift it away from the engine block.\u003c\/li\u003e\n  \u003cli\u003eThoroughly clean the engine's mounting surface to remove any old gasket material or corrosion.\u003c\/li\u003e\n  \u003cli\u003ePlace the new O-ring seal onto the new thermostat housing assembly.\u003c\/li\u003e\n  \u003cli\u003ePosition the new assembly onto the engine block and tighten the mounting bolts to the manufacturer's specified torque.\u003c\/li\u003e\n  \u003cli\u003eReconnect the coolant hoses and secure them with clamps.\u003c\/li\u003e\n  \u003cli\u003eRefill the cooling system with the appropriate coolant.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery, start the engine, and let it warm up, checking carefully for any leaks.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a failing thermostat or housing?\u003c\/summary\u003e\n  \u003cp\u003eCommon symptoms include engine overheating, engine temperatures that are too low, erratic temperature gauge readings, or visible coolant leaks from the housing area.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow can I confirm this kit fits my specific Verado engine?\u003c\/summary\u003e\n  \u003cp\u003eVerify your engine's model, horsepower, and year against our compatibility table. For precise confirmation, match your engine's serial number to the ranges listed in the 'Notes' column.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the difference between the OEM composite and aftermarket metal housings?\u003c\/summary\u003e\n  \u003cp\u003eThe original OEM housing is made of a durable composite material. Some aftermarket versions are made of a metal alloy. While metal can offer greater durability against impact, both materials are designed to perform to OEM cooling specifications.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs the O-ring seal included with this kit?\u003c\/summary\u003e\n  \u003cp\u003eYes, a new O-ring seal is included and is critical for ensuring a leak-proof installation. Always use the new seal provided.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should a thermostat be replaced on a Verado?\u003c\/summary\u003e\n  \u003cp\u003eAs a preventive maintenance item, it is often recommended to inspect and potentially replace the thermostat every 300 service hours or every 3 years, whichever comes first, or if any cooling issues are suspected.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n  \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50718268817723,"sku":"BD-EFSV-STYZ","price":32.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/BD-EFSV-STYZ.png?v=1762958648","url":"https:\/\/seasierra.com\/products\/thermostat-housing-kit-fits-mercury-mariner-verado-135-400-hp-replaces-892864t04-8m0174561","provider":"SeaSierra","version":"1.0","type":"link"}