{"product_id":"thermostat-kit-fits-mercury-mariner-verado-135-300hp-replaces-mercury-892864t04-sierra-18-3631","title":"Thermostat Kit – Fits Mercury\/Mariner Verado 135-300HP (Replaces Mercury 892864T04, Sierra 18-3631)","description":"\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\u003csection\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis \u003cstrong\u003eThermostat Kit for Mercury Verado 135-300 HP\u003c\/strong\u003e is designed for Mercury and Mariner Verado four-stroke outboard engines from 135HP to 300HP (2005–present). It plays a crucial role in maintaining optimal engine operating temperature by precisely regulating coolant flow, ensuring efficient performance and preventing overheating.\u003c\/p\u003e\n  \u003cp\u003eIt serves as a direct replacement for Mercury part numbers 892864T04 and 8M0174561, as well as Sierra 18-3631.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eEngineered for direct-fit installation.\u003c\/li\u003e\n    \u003cli\u003eMaintains a nominal opening temperature of 144°F (62°C).\u003c\/li\u003e\n    \u003cli\u003eIncludes the essential O-ring seal and clamp for a complete replacement.\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 brands.\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        \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        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eSierra\u003c\/td\u003e\n          \u003ctd\u003e18-3631\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 and year in the table below.\u003c\/p\u003e\n  \u003cp\u003eThis kit fits select four-stroke outboards under the Mercury and Mariner brands.\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 4-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e135\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 4-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e150\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 4-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e175\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 4-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e200\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 6-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e200\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 6-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e225\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 6-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e250\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 6-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e275\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003eVerado 6-Cylinder\u003c\/td\u003e\n          \u003ctd\u003e300\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2005–present\u003c\/td\u003e\n          \u003ctd\u003e892864T04\u003c\/td\u003e\n          \u003ctd\u003eAlso listed as 8M0174561\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 Kit with Housing\u003c\/dd\u003e\n    \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect Replacement\u003c\/dd\u003e\n    \u003cdt\u003eTemperature Rating\u003c\/dt\u003e\n\u003cdd\u003e144°F (62°C)\u003c\/dd\u003e\n    \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eAluminum\u003c\/dd\u003e\n    \u003cdt\u003eOperating Temperature\u003c\/dt\u003e\n\u003cdd\u003e144°F (62°C) nominal opening temperature\u003c\/dd\u003e\n    \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eIncludes O-ring seal and clamp\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 Assembly (replaces 892864T04)\u003c\/li\u003e\n    \u003cli\u003e1 x O-ring Seal (replaces 8M005958)\u003c\/li\u003e\n    \u003cli\u003e1 x Clamp (replaces 888988008)\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 cool, and disconnect the battery for safety.\u003c\/li\u003e\n    \u003cli\u003eDrain the engine coolant to a level below the thermostat housing.\u003c\/li\u003e\n    \u003cli\u003eLocate the thermostat housing. Remove any hoses and mounting bolts to access the old thermostat.\u003c\/li\u003e\n    \u003cli\u003eRemove the old thermostat, housing, and O-ring. Clean both mating surfaces of any old gasket material or corrosion.\u003c\/li\u003e\n    \u003cli\u003eInstall the new thermostat and O-ring into the housing. Ensure the thermostat is oriented correctly.\u003c\/li\u003e\n    \u003cli\u003eMount the new housing assembly and tighten the bolts to the manufacturer's specified torque.\u003c\/li\u003e\n    \u003cli\u003eReconnect all hoses and secure with clamps.\u003c\/li\u003e\n    \u003cli\u003eRefill the cooling system with the recommended coolant.\u003c\/li\u003e\n    \u003cli\u003eReconnect the battery, start the engine, and let it warm up. Check for any leaks and verify the engine reaches its normal operating temperature.\u003c\/li\u003e\n  \u003c\/ol\u003e\n\n  \u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I know if my thermostat is failing?\u003c\/summary\u003e\n    \u003cp\u003eCommon signs of a faulty thermostat include engine overheating alarms, the engine temperature gauge showing abnormally high or low readings, or erratic temperature fluctuations. A thermostat stuck open will prevent the engine from reaching its proper operating temperature, while one stuck closed will cause it to overheat quickly.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat is the operating temperature of this unit?\u003c\/summary\u003e\n    \u003cp\u003eThis thermostat is designed to begin opening at a nominal temperature of 144°F (62°C) to allow coolant to circulate through the engine block, effectively regulating its operating temperature.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWill this fit any Mercury Verado engine?\u003c\/summary\u003e\n    \u003cp\u003eThis kit is specifically designed for 4-cylinder and 6-cylinder Mercury Verado models from 135HP to 300HP manufactured from 2005 to the present. Always verify fitment by checking your OEM part number against the ones listed in our Part Number Matrix.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this a complete kit for the job?\u003c\/summary\u003e\n    \u003cp\u003eYes, this is a comprehensive kit that includes the thermostat, a new housing, the rubber O-ring seal, and the necessary clamp. This provides all the essential components for a standard thermostat replacement.\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). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, it is batch-inspected for consistency and reliability.\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 is 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\u003eThis product is covered by a 1-year warranty against manufacturing defects under normal use. If any issues arise, contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original condition. See our full 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 and specifications against 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 component, not an OEM part.\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 quality control.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50718269145403,"sku":"23TH632","price":32.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Thermostat_Kit_for_Mercury_Verado_135-175-200-225-250-275-300HP_18-3631_892864T04___18-3631_892864T04_-_JLM_MARINE-8291179.jpg?v=1762958661","url":"https:\/\/seasierra.com\/products\/thermostat-kit-fits-mercury-mariner-verado-135-300hp-replaces-mercury-892864t04-sierra-18-3631","provider":"SeaSierra","version":"1.0","type":"link"}