1362608 Replacing radiator sensor (N51)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2011 BMW 328xi, 2011 BMW 328i, 2010 BMW 328xi, 2010 BMW 328i, and 2009 BMW 328xi. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Scalding hazard!
Only perform this work after engine has cooled down.

WARNING: Poisonous gases!
Only perform this work with a dust extractor.

Necessary preliminary tasks:

REMOVE FAN COWL

Depiction of radiator sensor:

Sensor pin (1)
Snap hooks (2)

Fig 1: Identifying Sensor Pin And Snap Hooks
Courtesy of BMW OF NORTH AMERICA, INC.

Cut through snap hooks of radiator sensor with a hot appliance (if necessary, soldering iron).

WARNING: Do not inhale the poisonous gases created in the process.
Remove poisonous gases with an air extractor or fan.

Fig 2: Identifying Sensor Pin And Snap Hooks

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: When cutting through the snap hooks, do not damage the radiator and adjoining components.

Shear off stuck-in sensor pin of radiator sensor (1) by carefully turning housing.

Fig 3: Turning Radiator Sensor

Courtesy of BMW OF NORTH AMERICA, INC.

Remove cut-off snap hooks.

NOTE: This operation is necessary as otherwise the new sensor cannot be fitted.

Fig 4: Locating Snap Hooks

Courtesy of BMW OF NORTH AMERICA, INC.

Remove contaminants from bores (1 and 2) by blowing clear with compressed air.

In addition, fill bore (1) with suitable degreasing agent, e.g. brake cleaner (refer to BMW Parts Service) and wait approx. 1 minute.

Then remove degreasing agent completely from bore (1) by blowing clear with compressed air (bore must be dry).

Fig 5: Identifying Bores

Courtesy of BMW OF NORTH AMERICA, INC.

Clean sensor pin (1) with suitable degreasing agent and a fluff-free cloth.

NOTE:

Sensor pin must be dry before gluing.
Do not touch sensor pin with your fingers after it has been cleaned.
Carry out gluing immediately after cleaning.

Fig 6: Identifying Sensor Pin
Courtesy of BMW OF NORTH AMERICA, INC.

Insert adhesive (Loctite 4204) into bore (1) for sensor pin until adhesive emerges from bore.

If necessary, remove emerging adhesive with a fluff-free cloth.

Bore (1), see also Fig 5.

NOTE:

Adhesive application time: 20 secs.!
Components to be glued must be at room temperature!
Use only Loctite 4204 as adhesive.
Loctite 4204 adhesive is available from any good retailer.
Read and comply with Loctite's Technical Specifications.

Fig 7: Inserting Adhesive (Loctite 4204) Into Bore
Courtesy of BMW OF NORTH AMERICA, INC.

Insert sensor (1) into radiator bores until it snaps audibly into place. Do not tilt sensor in so doing.

NOTE:

Do not expose the sensor to movements or vibrations during the first 30 minutes.
Final strength is achieved after approx. 24 hours.

Fig 8: Inserting Sensor Into Radiator Bores
Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Read out fault memory of DME control unit.
Clear fault memory