{"product_id":"thermostat-fits-cummins-mercruiser-qsd-2-8l-4-2l-replaces-8m0093561-879194215","title":"Thermostat – Fits Cummins MerCruiser QSD 2.8L \u0026 4.2L (Replaces 8M0093561, 879194215)","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 replacement \u003cstrong\u003eThermostat – Fits Cummins MerCruiser QSD 2.8L \u0026amp; 4.2L Diesel Engines\u003c\/strong\u003e, ensuring your marine engine maintains the correct operating temperature for optimal performance and efficiency. It regulates coolant flow by opening at a precise 80°C (176°F) to prevent overheating and maintain stable conditions.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct replacement for Mercury MerCruiser part numbers 8M0093561, 879194215, 879194233, and 39012036F.\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003eEngineered for marine diesel engine cooling systems.\u003c\/li\u003e\n    \u003cli\u003eManufactured in an ISO 9002 certified facility to meet OEM specifications.\u003c\/li\u003e\n    \u003cli\u003eIncludes one thermostat ready for installation.\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\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury MerCruiser\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003ePrimary replacement\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury MerCruiser\u003c\/td\u003e\n        \u003ctd\u003e879194215\u003c\/td\u003e\n        \u003ctd\u003eInterchange\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury MerCruiser\u003c\/td\u003e\n        \u003ctd\u003e879194233\u003c\/td\u003e\n        \u003ctd\u003eInterchange\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury MerCruiser\u003c\/td\u003e\n        \u003ctd\u003e39012036F\u003c\/td\u003e\n        \u003ctd\u003eInterchange\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 compatible with the following Cummins MerCruiser Diesel (CMD) engine models.\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\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 EI 170\u003c\/td\u003e\n        \u003ctd\u003e170\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 EI 210\u003c\/td\u003e\n        \u003ctd\u003e210\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 EI 220\u003c\/td\u003e\n        \u003ctd\u003e220\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 EI 230\u003c\/td\u003e\n        \u003ctd\u003e230\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 ES 170\u003c\/td\u003e\n        \u003ctd\u003e170\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 ES 210\u003c\/td\u003e\n        \u003ctd\u003e210\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 ES 220\u003c\/td\u003e\n        \u003ctd\u003e220\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 2.8 ES 230\u003c\/td\u003e\n        \u003ctd\u003e230\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 4.2 EI 270\u003c\/td\u003e\n        \u003ctd\u003e270\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 4.2 EI 320\u003c\/td\u003e\n        \u003ctd\u003e320\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 4.2 EI 350\u003c\/td\u003e\n        \u003ctd\u003e350\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 4.2 ES 270\u003c\/td\u003e\n        \u003ctd\u003e270\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 4.2 ES 320\u003c\/td\u003e\n        \u003ctd\u003e320\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eCMD QSD 4.2 ES 350\u003c\/td\u003e\n        \u003ctd\u003e350\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e8M0093561\u003c\/td\u003e\n        \u003ctd\u003eDiesel engine\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\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eEngine cooling system\u003c\/dd\u003e\n  \u003cdt\u003eFuel Type\u003c\/dt\u003e\n\u003cdd\u003eDiesel\u003c\/dd\u003e\n  \u003cdt\u003eOpening Temperature\u003c\/dt\u003e\n\u003cdd\u003e80°C (176°F)\u003c\/dd\u003e\n  \u003cdt\u003eManufacturing\u003c\/dt\u003e\n\u003cdd\u003eManufactured to OEM specifications in ISO9002 certified factory\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e1 x\u003c\/span\u003e Thermostat (Replaces 8M0093561)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n    \u003cli\u003eEnsure the engine is completely cool before beginning work.\u003c\/li\u003e\n    \u003cli\u003eDrain the engine coolant into a suitable, clean container.\u003c\/li\u003e\n    \u003cli\u003eLocate and remove the thermostat housing. Note the orientation of the old thermostat.\u003c\/li\u003e\n    \u003cli\u003eRemove the old thermostat and thoroughly clean the mating surfaces of the housing and engine.\u003c\/li\u003e\n    \u003cli\u003eInstall the new thermostat, ensuring it is in the correct orientation. We highly recommend using a new gasket (not included) to ensure a leak-free seal.\u003c\/li\u003e\n    \u003cli\u003eRe-secure the housing and torque retaining bolts to the manufacturer's specification.\u003c\/li\u003e\n    \u003cli\u003eRefill the cooling system with the correct type and amount of coolant.\u003c\/li\u003e\n    \u003cli\u003eStart the engine, carefully check for any leaks, and monitor the temperature gauge to ensure the thermostat operates correctly.\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 engine's thermostat is failing?\u003c\/summary\u003e\n  \u003cp\u003eCommon signs of a faulty thermostat include engine overheating, the temperature gauge reading unusually high or low, poor cabin heater performance, and visible coolant leaks around the thermostat housing.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat temperature does this thermostat open at?\u003c\/summary\u003e\n  \u003cp\u003eThis thermostat is calibrated to begin opening at 80°C (176°F), ensuring your engine reaches and maintains its optimal operating temperature for performance and longevity.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs a gasket included with this thermostat?\u003c\/summary\u003e\n  \u003cp\u003eThis product includes the thermostat only. Gaskets or O-rings must be purchased separately. Using a new gasket is critical for a proper, leak-proof seal during installation.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eCan a bad thermostat cause my engine to run cold?\u003c\/summary\u003e\n  \u003cp\u003eYes. If a thermostat fails in the \"open\" position, it allows coolant to circulate constantly, preventing the engine from warming up to its proper operating temperature. This can lead to increased fuel consumption, higher emissions, and poor performance.\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\u003ePro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n    \u003cli\u003eFast Global Fulfillment — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n    \u003cli\u003eManufacturer-Direct Value — 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":50723787243835,"sku":"22TH040","price":63.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Thermostat_for_Cummins_MerCruiser_QSD_CMD_QSD_42_ES_320_QSD_28_8M0093561_-_JLM_MARINE-8291026.jpg?v=1763031750","url":"https:\/\/seasierra.com\/products\/thermostat-fits-cummins-mercruiser-qsd-2-8l-4-2l-replaces-8m0093561-879194215","provider":"SeaSierra","version":"1.0","type":"link"}