{"product_id":"bmw-e46-3-series-e53-x5-e83-x3-lci-aluminum-coolant-expansion-tank-reservoir-metal-radiator-overflow-header-tank-cooling-system-replacement-replaces-part-no-17117573781","title":"BMW E46 3 Series, E53 X5 \u0026 E83 X3 LCI Aluminum Coolant Expansion Tank Reservoir Kit – Metal Radiator Overflow Header Tank, Cooling System Replacement | Replaces Part No. 17117573781","description":"\u003cp data-pm-slice=\"1 1 []\"\u003e\u003cstrong\u003e\u003cspan\u003eUpgrade your BMW's cooling system with this aluminum coolant expansion tank reservoir, designed as an aftermarket replacement for select BMW E46 3 Series, E53 X5, and E83 X3 vehicles using the coolant reservoir identified by BMW part number 17117573781. The expansion tank is an essential component of the pressurized engine cooling system, accommodating coolant expansion as engine temperature rises while providing a designated location for coolant level monitoring and system filling. This aluminum replacement offers a metal alternative to the original plastic reservoir design, making it an appealing option for BMW owners replacing an aging, cracked, or leaking factory coolant tank.\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eBMW cooling systems operate under controlled pressure and experience repeated heating and cooling cycles during normal driving. Over time, the original plastic expansion tank can become brittle due to engine compartment temperatures, pressure fluctuations, and material aging. Cracks may develop around molded seams, hose connections, mounting areas, or other stressed sections of the reservoir. These failures can result in coolant leakage, declining coolant levels, and an increased risk of engine overheating.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis replacement coolant expansion tank is designed around the original reservoir application associated with BMW part number 17117573781. Its aluminum construction provides a metal alternative to the original plastic tank body while retaining the intended function of accommodating coolant expansion and supporting the vehicle's cooling system. Proper connection geometry, sealing surfaces, cap compatibility, and coolant level sensor provisions are essential for successful installation.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe expansion tank works with the radiator, thermostat, water pump, coolant hoses, and pressure cap to maintain proper cooling system operation. As coolant heats up and expands, the reservoir accommodates the resulting volume changes. When the engine cools, coolant volume decreases. The expansion tank and pressure cap are part of the system that manages these temperature-related changes.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eFor BMW owners maintaining an older E46, X3, or X5, replacing a deteriorated coolant expansion tank can help address a common source of coolant loss. An aluminum replacement may offer different durability characteristics from the factory plastic design, although overall reliability still depends on the quality of the tank's fabrication, welds, connections, seals, and installation.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eWhether restoring an aging cooling system, replacing a leaking reservoir, or selecting a metal expansion tank for a street-driven or performance-oriented BMW, this replacement provides an alternative to the original plastic component while preserving the intended coolant reservoir function on correctly matched vehicles.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eKey Features\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"true\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eAluminum Tank Construction:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Features an aluminum reservoir body as an alternative to the original plastic coolant expansion tank design.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46, E53 \u0026amp; E83 Applications:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Intended for select BMW 3 Series, X5, and X3 vehicles using the corresponding factory expansion tank configuration.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOEM Reference 17117573781:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Designed as an aftermarket replacement for the BMW coolant expansion tank identified by part number 17117573781.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eSupports Coolant Expansion Management:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Accommodates coolant volume changes that occur as the engine heats up and cools down.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eHelps Restore Cooling System Integrity:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Replacing a cracked or leaking reservoir can eliminate coolant loss originating from the original tank.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eMetal Alternative to Aging Plastic:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Offers an aluminum tank body for owners seeking a different construction material from the original molded plastic reservoir.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eDesigned for Pressurized Cooling Systems:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Intended to function within the corresponding BMW cooling system when equipped with the correct pressure cap, connections, and seals.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eFactory-Style Installation Location:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Designed to replace the original coolant expansion reservoir in its designated engine compartment position on compatible vehicles.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eSupports Coolant Level Monitoring:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The correct replacement configuration must accommodate the vehicle's applicable coolant level sensor and mounting arrangement.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eSuitable for Cooling System Maintenance:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Can be installed during cooling system refurbishment involving hoses, radiator components, thermostat replacement, or water pump service.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eReplacing a deteriorated coolant expansion tank is an important part of maintaining a reliable BMW cooling system. This aluminum reservoir provides an aftermarket alternative to the original plastic tank and is intended to help restore proper coolant containment and expansion capacity when installed on a compatible vehicle.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eFITMENT: BMW E46 3 Series, E53 X5 \u0026amp; E83 X3\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46 3 Series Sedan\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 320i – Select 2001–2005 applications\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 323i – 1999–2000\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 325i – 2001–2005\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 325xi – 2001–2005\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 328i – 1999–2000\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 330i – 2001–2005\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 330xi – 2001–2005\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46 3 Series Coupe\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 323Ci – 2000\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 325Ci – 2001–2006\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 328Ci – 2000\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 330Ci – 2001–2006\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46 3 Series Convertible\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 323Ci Convertible – Select early applications\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 325Ci Convertible – 2001–2006\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 330Ci Convertible – 2001–2006\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46 3 Series Touring\/Wagon\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 323i Touring – Select markets\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 325i Touring – 2001–2005\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E46 325xi Touring – 2001–2005\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E53 X5\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E53 X5 3.0i – M54B30 3.0L, approximately 2001–2006\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E83 X3 – Pre-Facelift\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E83 X3 2.0i – N46 2.0L, select markets\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E83 X3 2.5i – M54B25 2.5L\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E83 X3 3.0i – M54B30 3.0L\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E83 X3 LCI – Facelift\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E83 X3 2.0i – N46 2.0L, select markets\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E83 X3 2.5si – N52-family 2.5L, select markets\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBMW E83 X3 3.0si – N52-family 3.0L\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eImportant Fitment Information\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eBMW's original expansion tank part number 17117573781 is documented across E46, E53, and E83 applications. However, the fitment of the original BMW plastic tank does not independently guarantee that every aftermarket aluminum version will clear surrounding components or accept all original connections.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eFor the aluminum replacement, customers must confirm:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOriginal BMW reservoir part number\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eVehicle VIN and production date\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eEngine configuration\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eTransmission-related cooling system configuration\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eReservoir mounting arrangement\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHose connection positions\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eCoolant level sensor compatibility\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePressure cap compatibility\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46 M3 models are not included in this listing.\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The E46 M3 uses a different cooling system arrangement and should not be assumed compatible.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eBMW E53 X5 V8 and diesel models are also not included in the confirmed scope of this listing.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eEngine Compatibility\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW M52TU Inline-Six Engines\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eM52TUB25 – 2.5L gasoline\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eM52TUB28 – 2.8L gasoline\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW M54 Inline-Six Engines\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eM54B22 – 2.2L gasoline\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eM54B25 – 2.5L gasoline\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eM54B30 – 3.0L gasoline\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW N46 Four-Cylinder Engines\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eN46-family 2.0L gasoline engines in select E83 X3 applications\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW N52 Inline-Six Engines\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eN52-family 2.5L gasoline engines in select E83 X3 LCI applications\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eN52-family 3.0L gasoline engines in select E83 X3 LCI applications\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eAdditional E46 Engine Variants\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eCertain four-cylinder E46 vehicles may also use the original BMW expansion tank reference, but exact aftermarket aluminum tank compatibility must be verified individually.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOEM Replacement Part Numbers\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePrimary BMW Reference\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e17117573781\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e17 11 7 573 781\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eDocumented Earlier BMW References\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e17137787039\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e17111436413\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThe primary BMW part number 17117573781 supersedes earlier expansion tank references in the original BMW parts catalog.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThese references identify the factory coolant expansion tank application. They do not establish that the aluminum replacement is manufactured by BMW or that it has identical material construction.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eInstallation\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003col data-spread=\"false\" start=\"1\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePark the vehicle securely on a level surface.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eSwitch off the engine and allow the cooling system to cool completely.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eNever remove the coolant expansion tank cap while the engine is hot or the system is pressurized.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eConfirm the replacement aluminum tank matches the original reservoir configuration.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eInspect the new tank for visible damage, incomplete welds, damaged fittings, or irregular sealing surfaces.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eRemove any engine covers, intake components, or surrounding trim required for access.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eLocate the original coolant expansion tank.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eInspect the original reservoir for cracks, leaks, coolant residue, or damaged connections.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePosition a suitable drain container beneath the cooling system.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDrain the required amount of coolant according to the applicable BMW service procedure.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDisconnect the coolant level sensor electrical connector, where fitted.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eRemove the coolant level sensor if it must be transferred to the replacement tank.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eCarefully disconnect the coolant hoses and retaining clips from the original reservoir.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eAvoid damaging brittle plastic hose fittings during removal.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eRelease the reservoir from its mounting bracket or retaining mechanism.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eRemove the original expansion tank from the vehicle.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eCompare the original and replacement tanks for height, width, connection positions, mounting points, and clearance.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eVerify that the replacement tank accepts the correct pressure cap.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eConfirm compatibility with the original coolant level sensor or the sensor supplied with the replacement, if applicable.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eInspect all required O-rings, sealing rings, hose fittings, and retaining clips.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eReplace damaged seals and connectors before installation.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eInstall the replacement aluminum tank in the designated mounting location.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eSecure the tank using the appropriate mounting arrangement.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eReconnect all coolant hoses to their corresponding fittings.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eEnsure that each hose is properly seated and securely retained.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eReinstall or connect the coolant level sensor where applicable.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eVerify that the tank and hoses do not contact moving components or interfere with surrounding engine parts.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eReinstall any removed engine covers or intake components.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eRefill the cooling system using coolant that meets the vehicle's applicable BMW specification.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBleed the cooling system according to the correct vehicle-specific procedure.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eInspect the reservoir, welds, fittings, and hose connections for coolant leakage.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eMonitor engine temperature while confirming normal cooling system operation.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eAllow the engine to cool and recheck the coolant level.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePerform a cooling system pressure test when appropriate.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eReinspect the reservoir and surrounding connections after initial operation.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eImportant Cooling System Safety Information\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe BMW cooling system operates under pressure and can cause serious burns if opened while hot.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA leaking expansion tank can result in rapid coolant loss and engine overheating.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eDo not continue driving if the vehicle overheats, coolant loss is substantial, or the replacement tank cannot maintain a secure seal.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eAluminum construction does not eliminate the need to inspect hose fittings, seals, radiator components, and the pressure cap.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCompatibility Notes\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-spread=\"true\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW Part Number 17117573781:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The primary OE reference identifies a coolant expansion tank used in select E46, E53, and E83 cooling systems.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eAluminum Aftermarket Construction:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e This product is described as an aluminum replacement. The original BMW expansion tank is plastic. Do not describe the aluminum version as a factory BMW aluminum tank.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46 Non-M Applications:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The OE reference covers multiple non-M E46 3 Series configurations. Exact aluminum replacement fitment must be verified.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E46 M3 Exclusion:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Do not advertise E46 M3 compatibility without a separate verified application.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E53 X5 Compatibility:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The documented X5 application is the E53 X5 3.0i with the M54 inline-six engine.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E53 V8 Exclusion:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Do not assume compatibility with the X5 4.4i, 4.6is, or 4.8is.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E83 X3 Compatibility:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The OE reference is associated with select first-generation X3 vehicles.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBMW E83 LCI Compatibility:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e BMW catalogs include facelift E83 X3 applications, including select N52-powered models.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eNot All X3 Engines Are Included:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Diesel and other engine variants require individual part-number confirmation.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eTransmission Configuration Matters:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e BMW cooling system layouts can vary with manual and automatic transmission equipment. Verify the original reservoir and associated mounting arrangement.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCheck the Reservoir Mounting Bracket:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The aluminum tank must fit the original mounting location without interference or unsupported modification.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eVerify Hose Connection Geometry:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The replacement tank must match the original coolant hose positions, connector diameters, and sealing arrangements.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCheck Pressure Cap Compatibility:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The reservoir must accept a pressure cap with the correct specifications for the vehicle.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePressure Cap May Be Sold Separately:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Do not assume that a radiator or expansion tank pressure cap is included.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCoolant Level Sensor Compatibility:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Verify that the aluminum tank supports the required sensor configuration and that the sensor operates correctly after installation.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCoolant Level Sensor May Be Sold Separately:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The original BMW tank is commonly supplied without the sensor. Confirm the actual aluminum product's package contents.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eSealing Rings and O-Rings:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Confirm that all required seals are included or available separately. The OE tank reference does not guarantee that every seal is supplied.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eTank Material Does Not Guarantee Better Cooling:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e An aluminum expansion tank does not automatically reduce engine operating temperature or increase radiator cooling capacity.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eNo Guaranteed Elimination of Cooling Problems:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Replacing the reservoir will not correct a defective thermostat, water pump, radiator, cooling fan, or unrelated coolant leak.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eInspect Existing Coolant Hoses:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Aging hoses may crack or leak when disturbed during reservoir replacement.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eInspect the Thermostat:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e A malfunctioning thermostat can cause overheating independently of the expansion tank.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eInspect the Water Pump:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Water pump failure or leakage can cause coolant circulation problems and overheating.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCheck the Radiator:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e A leaking or restricted radiator requires separate diagnosis and repair.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCorrect Coolant Required:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Use coolant meeting the applicable BMW specification and follow the vehicle's specified mixture requirements.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eProper Bleeding Is Essential:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Air trapped in the cooling system can cause overheating, inconsistent heater performance, or abnormal coolant level behavior.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCorrosion Compatibility:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The replacement tank's aluminum construction must be suitable for the vehicle's coolant chemistry. Use the correct coolant and avoid incompatible additives.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eWeld Quality Matters:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Aluminum tank reliability depends partly on weld integrity, manufacturing quality, and sealing surfaces. Inspect the actual product before installation.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eNo Verified Tank Capacity:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Do not advertise a specific reservoir volume without confirmed product specifications.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eNo Verified Aluminum Grade:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Do not claim a particular aluminum alloy, wall thickness, or fabrication process unless documented by the supplier.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eNo Verified Pressure Rating:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Do not advertise a maximum operating pressure without manufacturer documentation.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eNot a Complete Cooling System Kit:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e This listing covers the coolant expansion reservoir, not the radiator, thermostat, water pump, or complete hose system.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eConfirm Included Components:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The cap, coolant level sensor, mounting hardware, seals, and hoses must be listed separately unless confirmed as included.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOriginal BMW Supersessions:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Earlier OE references include 17137787039 and 17111436413. These apply to the original BMW parts catalog and do not independently verify the physical fit of every aftermarket aluminum version.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOEM Reference vs. Genuine BMW:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e This is an aftermarket aluminum replacement and should not be described as Genuine BMW.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eVIN Verification Recommended:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Confirm the vehicle's original reservoir part number, production date, transmission configuration, and cooling system layout before purchasing.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eLong-Term Cooling System Reliability\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eMaintaining a properly sealed coolant expansion tank is essential for the reliability of BMW E46, E53 X5, and E83 X3 cooling systems. As original plastic reservoirs age, repeated pressure and temperature cycles can contribute to cracking, coolant seepage, and unexpected fluid loss.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis aluminum coolant expansion tank provides a metal replacement option for compatible vehicles using BMW part number 17117573781. When manufactured to the correct specifications and properly installed, it can help restore coolant containment and maintain the intended expansion reservoir function.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eFor BMW owners replacing aging cooling system components or undertaking a comprehensive cooling system refurbishment, selecting the correct reservoir, inspecting related hoses and seals, using the proper coolant, and thoroughly bleeding the system are essential steps toward dependable engine cooling performance.\u003c\/span\u003e\u003c\/p\u003e","brand":"BAVMODS®","offers":[{"title":"Default Title","offer_id":49354782146750,"sku":null,"price":405.16,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0619\/8788\/1150\/files\/6E485C25-A3E1-47DC-91D3-4ACA46F916C9_1_201_a.jpg?v=1793909261","url":"https:\/\/bavmods.com\/de\/products\/bmw-e46-3-series-e53-x5-e83-x3-lci-aluminum-coolant-expansion-tank-reservoir-metal-radiator-overflow-header-tank-cooling-system-replacement-replaces-part-no-17117573781","provider":"BAVMODS®","version":"1.0","type":"link"}