BMW Coolant Expansion Tank Reservoir – OEM Cooling System Replacement, Restores Cooling System Reliability for E46, E53, E83, E85 & E86 Models | Replaces Part No. 17137787039

Restore 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.

The 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.

Manufactured 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.

Whether 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.

Key Features:

• Direct OEM Replacement: Designed to replace the factory coolant expansion tank reservoir on compatible BMW applications.
• Replaces Worn, Cracked, or Leaking Reservoirs: A smart solution for one of the most common BMW cooling system failure points.
• Restores Proper Coolant Management and System Pressure: Helps maintain correct coolant expansion and dependable cooling system function.
• Helps Prevent Coolant Loss and Overheating: Replacing a weakened expansion tank can help reduce the risk of leaks and temperature-related engine issues.
• Supports Proper Engine Operating Temperatures: Helps the cooling system perform correctly under normal and demanding driving conditions.
• High-Strength Heat-Resistant Construction: Built to withstand repeated heat cycles and cooling system pressure.
• Precision-Molded OEM-Style Fitment: Designed to match the original installation layout for secure fitment and proper function.
• Ideal for Repairs and Preventative Maintenance: A critical cooling system replacement for aging BMW platforms.

FITMENT:

• BMW 3 Series – E46 Sedan, Coupe, Touring, Convertible
  Compatible with 325i, 325xi, 330i, and 330xi models.
• BMW X3 – E83 SUV
  Compatible with X3 2.5i and X3 3.0i models.
• BMW X5 – E53 SUV
  Compatible with X5 3.0i models.
• BMW Z4 – E85 Roadster
  Compatible with Z4 2.5i, Z4 3.0i, and Z4 M Roadster models.
• BMW Z4 – E86 Coupe
  Compatible with Z4 Coupe 3.0si and Z4 M Coupe models.

If 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.

REPLACES PART NO.: 17137787039, 171377870, 17117573781

Please refer to the “Fitment” section in the product description for compatibility details.