17 11 100 Removing and installing/replacing coolant expansion tank

WARNING: This page is about a different car, the 2003 BMW 525i, 2002 BMW 525i, and 2001 BMW 525i. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Danger of scalding! Open cap on coolant expansion tank only after engine has cooled down.

Drain coolant to below level of coolant expansion tank only.

Disconnect plug from level sensor.

Fig 1: Disconnecting Plug From Level Sensor

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Release clamp and detach hose from coolant expansion tank.

Fig 2: Releasing Clamp & Detaching Hose From Coolant Expansion Tank

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Open cap on coolant expansion tank.

Remove vent plug completely.

Fig 3: Removing Coolant Expansion Tank Cap

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Unclip retaining cap.

Fig 4: Releasing Retaining Cap

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Pull expansion tank towards rear and detach vent hose.

Fig 5: Removing Expansion Tank & Detaching Vent Hose

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Lift coolant expansion tank out of lower retaining lugs.

Installation:

The retaining lugs on the expansion tank must locate in the fan cowl.

Top up with recommended coolant only.

Vent cooling system and check for leaks.

Fig 6: Removing Coolant Expansion Tank

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WARNING: Danger of scalding! Open cap on coolant expansion tank only after engine has cooled down.

Drain coolant to below level of coolant expansion tank only.

Follow instructions for working on cooling system.

CAUTION: Do not allow coolant to come into contact with eyes.

NOTE: For a better overview, this work step is shown from below.

Lower car and carry out work from above.

Pull out locks (1) of water hoses (2). Detach water hoses (2) from coolant expansion tank.

Recycling:

Catch and dispose of coolant.

Fig 1: Detaching Water Hoses

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Disconnect plug (3) from level sensor.

Remove vent plug completely.

Fig 2: Removing Vent Plug

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Unclip retaining cap.

Fig 3: Releasing Retaining Cap

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Pull expansion tank towards rear and detach vent hose.

Fig 4: Removing Expansion Tank & Detaching Vent Hose

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Lift coolant expansion tank out of lower retaining lugs.

Installation:

The retaining lugs on the expansion tank must locate in the fan cowl.

Top up with recommended coolant only.

Vent cooling system and check for leaks.

Fig 5: Removing Coolant Expansion From Lower Retaining Lugs

Courtesy of BMW OF NORTH AMERICA, INC.