How to Replace Coolant Reservoir 01-05 BMW 325Xi

Difficulty: Advanced · About 90 min · Bmw 325xi

Replace the coolant expansion reservoir on a 2001–2005 BMW 325xi and refill and bleed the system after restoring all hose connections.

Steps

1. Cool the engine and remove the fan shroud

   Wait until the engine is completely cold, disconnect the negative battery cable, and drain coolant into a pan. Release the air collector retainers and shroud fasteners, unplug the fan wiring, then remove the fan clutch with the correct reverse-thread tool and lift the fan and shroud out.

2. Remove the air box and reservoir

   Unplug the airflow sensor, release the intake clamp and air box latches, remove the filter and air box bolts, and lift the assembly out. Disconnect the reservoir hoses by releasing their clips, remove its mounting screws, unplug the level sensor, and lift the tank straight off its connections.

3. Install the replacement reservoir

   Reconnect the level sensor, lower the new reservoir onto its fittings, and lock its retaining lever. Reattach each coolant hose until its clip locks, reinstall the reservoir and radiator screws, and reconnect upper radiator hoses securely.

4. Reinstall the shroud and intake

   Lower the fan and shroud into place, reconnect its plugs, and install its retainers and fasteners. Refit the air box, filter, intake duct and airflow sensor connector, then reconnect the battery.

5. Fill and bleed the cooling system

   Use the specified coolant and the vehicle's bleeding procedure, opening the designated bleeder only when directed. Run the heater and engine as specified while watching temperature and leaks, then let the engine cool completely and recheck the level.

Check your vehicle’s repair manual for exact specifications and fit.