{"product_id":"bmw-coolant-expansion-tank-reservoir-replacement-restores-cooling-system-reliability-e46-e53-e83-e85-e86-3-series-x3-x5-z4-17137787039","title":"BMW Coolant Expansion Tank Reservoir – OEM Cooling System Replacement, Restores Cooling System Reliability for E46, E53, E83, E85 \u0026 E86 Models | Replaces Part No. 17137787039","description":"\u003cp class=\"p1\"\u003e\u003cstrong\u003eRestore proper cooling system function and maintain reliable engine temperatures with this OEM-style Coolant Expansion Tank Reservoir replacement for select BMW E46, E53, E83, E85, and E86 models. Designed to replace the factory coolant reservoir, this component plays a critical role in managing coolant expansion, maintaining system pressure, and supporting efficient cooling system operation.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe expansion tank is one of the most common BMW cooling system service items. Over time, factory reservoirs can become brittle from repeated heat cycles and pressure fluctuations, eventually leading to cracks, coolant leaks, warning lights, and potential overheating issues. Replacing a worn expansion tank is one of the most important preventative maintenance steps you can take to help protect the engine and cooling system from costly damage.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eManufactured from durable automotive-grade materials, this replacement coolant reservoir is built to withstand demanding operating temperatures and cooling system pressure. The precision-molded design helps ensure OEM-style fitment and smooth integration with factory cooling system components for dependable long-term performance.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eWhether you are repairing a coolant leak, replacing a failed expansion tank, or refreshing an aging cooling system, this direct-fit replacement helps restore factory cooling performance and long-term reliability without requiring modifications.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003e\u003cstrong\u003eKey Features:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003eDirect OEM Replacement: Designed to replace the factory coolant expansion tank reservoir on compatible BMW applications.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eReplaces Worn, Cracked, or Leaking Reservoirs: A smart solution for one of the most common BMW cooling system failure points.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eRestores Proper Coolant Management and System Pressure: Helps maintain correct coolant expansion and dependable cooling system function.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eHelps Prevent Coolant Loss and Overheating: Replacing a weakened expansion tank can help reduce the risk of leaks and temperature-related engine issues.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eSupports Proper Engine Operating Temperatures: Helps the cooling system perform correctly under normal and demanding driving conditions.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eHigh-Strength Heat-Resistant Construction: Built to withstand repeated heat cycles and cooling system pressure.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003ePrecision-Molded OEM-Style Fitment: Designed to match the original installation layout for secure fitment and proper function.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eIdeal for Repairs and Preventative Maintenance: A critical cooling system replacement for aging BMW platforms.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003e\u003cb\u003eFITMENT:\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003eBMW 3 Series – E46 Sedan, Coupe, Touring, Convertible\u003cbr\u003eCompatible with 325i, 325xi, 330i, and 330xi models.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eBMW X3 – E83 SUV\u003cbr\u003eCompatible with X3 2.5i and X3 3.0i models.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eBMW X5 – E53 SUV\u003cbr\u003eCompatible with X5 3.0i models.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eBMW Z4 – E85 Roadster\u003cbr\u003eCompatible with Z4 2.5i, Z4 3.0i, and Z4 M Roadster models.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eBMW Z4 – E86 Coupe\u003cbr\u003eCompatible with Z4 Coupe 3.0si and Z4 M Coupe models.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003eIf you’re unsure whether this coolant expansion tank fits your specific vehicle, please contact us with your VIN and we’ll be happy to verify compatibility before you order.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003e\u003cb\u003eREPLACES PART NO.: \u003c\/b\u003e17137787039, 171377870, 17117573781\u003c\/p\u003e","brand":"BAVMODS®","offers":[{"title":"Default Title","offer_id":47618400944318,"sku":null,"price":80.48,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0619\/8788\/1150\/files\/1_12d5b2f0-4488-470a-a837-76b3cbdd787d.jpg?v=1781071222","url":"https:\/\/bavmods.com\/de\/products\/bmw-coolant-expansion-tank-reservoir-replacement-restores-cooling-system-reliability-e46-e53-e83-e85-e86-3-series-x3-x5-z4-17137787039","provider":"BAVMODS®","version":"1.0","type":"link"}