{"product_id":"c-tzu-aluminum-thermostat-housing-assembly-for-bmw-1999-2006-direct-fit-97-c-thermostat","title":"C-Tzu Aluminium Thermostat Housing Assembly for BMW 1999–2006 – Direct-Fit, 97°C Thermostat","description":"\u003cp\u003e\u003cstrong\u003eC-Tzu’s aluminum thermostat housing assembly is a direct-fit replacement built to restore proper coolant control on select BMW 323, 325, 328, 330, 525, 528, 530, X3, X5, Z3 and Z4 models from 1999–2006.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis heavy-duty assembly replaces multiple OEM part numbers and is engineered to match original mounting points and coolant passages so you can quickly replace a leaking or failed thermostat housing. Machined from aluminum with a precision thermostat calibrated to open at approximately 97 °C (206.6 °F), the unit is intended to provide a reliable seal and long service life under normal operating conditions.\u003c\/p\u003e\n\n\u003ch3\u003eHow will this assembly fit my BMW and which part numbers does it replace?\u003c\/h3\u003e\n\u003cp\u003eThe C-Tzu housing is manufactured to meet the dimensional and mounting specifications of the original equipment for the listed BMW models. It is designed as a bolt-on replacement so you won’t need modifications to your vehicle’s coolant system.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eReplacement for OEM numbers: 11537509227, 11531437040, 11531436823 and related variants.\u003c\/li\u003e\n  \u003cli\u003eEngineered to match original bolt pattern and hose connections for direct installation.\u003c\/li\u003e\n  \u003cli\u003eCompatible with 1999–2006 BMW models including 3-series, 5-series, X3, X5, Z3 and Z4.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat materials and thermostat specifications are used in this unit?\u003c\/h3\u003e\n\u003cp\u003eThe housing is constructed from aluminum for improved thermal conductivity and resistance to corrosion compared with lower-grade materials. The thermostat element is set to open at roughly 97 °C to regulate coolant flow at standard operating temperatures.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAluminum construction for durability and consistent heat transfer.\u003c\/li\u003e\n  \u003cli\u003eThermostat opening temperature: approximately 97 °C \/ 206.6 °F.\u003c\/li\u003e\n  \u003cli\u003eHigh-tolerance machining for accurate sealing surfaces and fitment.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow straightforward is the installation and what tools will I need?\u003c\/h3\u003e\n\u003cp\u003eThis part is designed as a direct OEM-style replacement, so installation is typically straightforward for anyone with basic automotive tools and mechanical experience. You’ll remove the old housing, swap in the new unit, and torque fasteners to factory specifications.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eNo special tools or custom modifications required for most installs.\u003c\/li\u003e\n  \u003cli\u003eBasic tools: metric socket set, torque wrench, coolant drain pan and new gasket or sealant as recommended.\u003c\/li\u003e\n  \u003cli\u003eFollow vehicle service manual torque specs and bleeding procedure for the coolant system.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat performance and reliability can I expect from this C-Tzu housing?\u003c\/h3\u003e\n\u003cp\u003eThe assembly is designed to reduce the chance of coolant leaks and provide stable thermostat operation when installed correctly. Proper sealing surfaces and corrosion-resistant aluminum construction contribute to longer service intervals under normal conditions.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eHigh sealing capability to help prevent leaks at the housing flange and hose connections.\u003c\/li\u003e\n  \u003cli\u003eDurable design intended for long-term service when used with correct installation practices.\u003c\/li\u003e\n  \u003cli\u003eBacked by a 30-day satisfaction guarantee for peace of mind after purchase.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: The C-Tzu aluminum thermostat housing assembly is aimed at DIY mechanics and professional technicians working on BMW E46, E39, E53, E83, and related platforms from 1999–2006 who need a reliable, OEM-compatible replacement. It’s suitable for owners addressing leaks, overheating caused by failed housings, or anyone restoring coolant-system integrity with a direct-fit aftermarket option.\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 thermostat housing fit my 2003 BMW 325i?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes — this C-Tzu housing is a direct replacement for many 2003 BMW 325i models that use the listed OEM numbers; confirm your OEM part number before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does the thermostat open at a specific temperature?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: The thermostat in this assembly is calibrated to open at approximately 97 °C (206.6 °F).\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"C-Tzu","offers":[{"title":"Default Title","offer_id":55167706988887,"sku":"B0D1XZX1SP","price":45.13,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/c-tzu-thermostat-housing-front-view_f95ebcc9-bed6-4e58-84d0-5c66819cdbab.jpg?v=1790391465","url":"https:\/\/britishgarage.co.uk\/products\/c-tzu-aluminum-thermostat-housing-assembly-for-bmw-1999-2006-direct-fit-97-c-thermostat","provider":"British Garage","version":"1.0","type":"link"}