{"product_id":"ghmarine-thermostat-service-kit-for-mercruiser-4-3-7-4l-v6-v8-140-f-thermostat-plus-gaskets-o-ring","title":"GHmarine Thermostat Service Kit for Mercruiser 4.3–7.4L V6\/V8 - 140°F Thermostat plus Gaskets \u0026 O-ring","description":"\u003cp\u003e\u003cstrong\u003eGHmarine 18-3668 is a complete thermostat service kit designed to restore correct operating temperature control on Mercruiser 4.3–7.4L V6 and V8 sterndrive engines.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eKeeping your Mercruiser engine running at the right temperature prevents overheating and improves performance; this GHmarine kit supplies a 140°F thermostat plus sealing parts to replace worn components on compatible GM-based Mercruiser sterndrives. The kit matches common OE part numbers, includes multiple gaskets and an O-ring, and fits a range of V6 and V8 marine sterndrive models so you can complete the repair in one visit to the workbench.\u003c\/p\u003e\n\n\u003ch3\u003eWhich engines and applications does this thermostat kit fit?\u003c\/h3\u003e\n\u003cp\u003eThis GHmarine thermostat service kit is made for Mercruiser sterndrive engines built on GM blocks with displacements from 4.3L up to 7.4L, covering both V6 and V8 configurations. It replaces a number of original and aftermarket part numbers to ensure broad compatibility with many common Mercruiser models.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eFits Mercruiser 4.3L through 7.4L GM V6 and V8 sterndrive engines\u003c\/li\u003e\n  \u003cli\u003eDirect replacement for Mercruiser OE part numbers like 807252Q4 and 807252T4\u003c\/li\u003e\n  \u003cli\u003eAlso replaces Sierra 18-3668, Mallory 9-43150 and GLM 13390 equivalents\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat components are included and what temperature does the thermostat regulate?\u003c\/h3\u003e\n\u003cp\u003eThe kit contains the thermostat itself, a precision O-ring, and five different thermostat gaskets to accommodate installation variations. The thermostat opens at an approximate 140°F temperature rating—chosen to match typical Mercruiser cooling specifications for reliable engine temperature control.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eOne 140°F cooling thermostat calibrated for marine use\u003c\/li\u003e\n  \u003cli\u003eOne replacement O-ring to ensure a watertight seal\u003c\/li\u003e\n  \u003cli\u003eFive thermostat gaskets included for correct flange mating\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow does this kit simplify installation and maintenance?\u003c\/h3\u003e\n\u003cp\u003eBy supplying the thermostat plus both a seal and multiple gaskets, GHmarine minimizes trips to the parts store and helps avoid rework if the original gasket is damaged. The included components let technicians and DIYers complete a proper service without locating separate seals or adaptors.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eComplete kit reduces need for additional parts during service\u003c\/li\u003e\n  \u003cli\u003eMultiple gaskets cover different housing surfaces and tolerances\u003c\/li\u003e\n  \u003cli\u003eO-ring replacement improves leak resistance after reassembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eAre there cross-references to original equipment and aftermarket part numbers?\u003c\/h3\u003e\n\u003cp\u003eYes—this GHmarine kit is engineered to act as a direct substitute for several Mercruiser and aftermarket references, helping you match parts quickly when servicing older or common sterndrive models. Verifying part numbers against your engine manual ensures the best fit.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eReplaces Mercruiser 807252Q4, 807252T4, 807252T7 and related numbers\u003c\/li\u003e\n  \u003cli\u003eAlso listed as replacements for 59137, 807252T1 and 8M0089715\u003c\/li\u003e\n  \u003cli\u003eCross-referenced to GLM 13390, Mallory 9-43150 and Sierra 18-3668\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho this kit is for: Marine technicians, boat owners, and do-it-yourselfers who maintain Mercruiser sterndrive engines and need a reliable thermostat replacement with all necessary seals on hand. If you operate or service GM-based 4.3–7.4L Mercruiser V6 or V8 sterndrives and want a ready-to-install thermostat solution that matches common OEM and aftermarket numbers, this GHmarine 18-3668 service kit is engineered to make the job straightforward and leak-free.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Will this kit fit my Mercruiser 5.7L V8 sterndrive?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. The GHmarine 18-3668 kit fits Mercruiser GM-based 4.3–7.4L V6 and V8 sterndrive engines, including most 5.7L models.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does the kit include everything needed to prevent leaks?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: The kit includes a thermostat, one O-ring and five gaskets to ensure proper sealing and reduce leak risk during installation.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"GHmarine","offers":[{"title":"Default Title","offer_id":48083017891998,"sku":"B0D1N2RZ5S","price":51.04,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/ghmarine-thermostat-kit-front-packaging.jpg?v=1785822727","url":"https:\/\/northtrailauto.ca\/products\/ghmarine-thermostat-service-kit-for-mercruiser-4-3-7-4l-v6-v8-140-f-thermostat-plus-gaskets-o-ring","provider":"North Trail Auto","version":"1.0","type":"link"}