Rein 80A-121-405 AQ Coolant Expansion Tank

The Rein 80A-121-405 AQ is a direct-fit OE-replacement coolant expansion tank (also known as a coolant reservoir or overflow tank) designed to restore proper cooling system function. Engineered to match original equipment specifications, this tank maintains the correct coolant level and allows the cooling system to breathe as fluid expands and contracts with engine temperature changes.

Key Features:

• Direct OEM replacement — matches original fit, form, and function
• Manufactured from high-quality, heat-resistant plastic for long-term durability
• Includes integrated mounting points for a secure, rattle-free installation
• Compatible with OEM part number 80A-121-405 AQ
• Designed to meet or exceed original equipment standards
• Helps maintain proper coolant pressure and prevent overheating

Rein Automotive specializes in European vehicle replacement parts and is recognized for producing components that meet strict OE quality benchmarks. This coolant expansion tank is a reliable, cost-effective solution for restoring a leaking, cracked, or damaged factory reservoir.