Engine Coolant Overflow Tank 603-638 Direct Fit Replacement For Audi A4 A4 Quattro 2002 2009 2.0L 1.8L 3.2L V6 Includes 8E0121403 FRT1108C 603638 Coolant Reservoir Tank Durable Plastic Construction Easy Install Keeps Coolant Pressurized And Leaks Free
✔️ Direct-fit 603-638 coolant tank for Audi A4, quick install
This direct-fit coolant overflow tank replaces the OE 603638 reservoir in Audi A4 models from 2002 to 2009, including 2.0L, 1.8L, and 3.2L engines. It sits in the cooling system to capture excess coolant and return it to the radiator as the engine cools, helping maintain proper pressure and prevent leaks.
✅ OE-standard compatibility: 603638, Z49037, 8E0121403, 376737131, APET0134, DAKG-21403M, FRT1108C, SK603638
✅ Material: durable PP plastic designed to resist heat and vibration
✅ Function: stores excess coolant and makes antifreeze level visible without removing the cap
✅ Easy install: direct-fit replacement with OE-style connections for Audi A4
💡 What is an engine coolant overflow tank used for and why pick a direct-fit replacement? This handy component helps manage coolant expansion and keeps the cooling system sealed. - Maintains proper coolant level and system pressure - Reduces risk of overheating and coolant loss - OE-style fit simplifies replacement on Audi A4 2002-2009