TIS Service Bulletin

SI B11 03 08
Engine

Page 1 of 3

July 2018
Technical Service

CRANKCASE VENTILATION SYSTEM DIAGNOSIS AND
MEASUREMENT
New information provided by this revision is preceded by this symbol

.

This Service Information bulletin replaces SI B11 03 08 dated July 2017
What’s New:
• BXX engine specifications diagnostic tips updated
• Basic diagnostic tips updated

MODEL
All

INFORMATION
All current BMW engines incorporate a pressure-controlled crankcase ventilation system. The crankcase
ventilation systems use various different crankcase ventilation valves, depending on the engine type. Although
the valves all look different, they function similarly, using a spring and diaphragm assembly to control the
crankcase pressure. A properly functioning pressure control valve is designed to maintain a slight vacuum
(under-pressure) in the crankcase, which assures reliable crankcase venting during all engine operating
conditions. Some of the causes and results of a malfunctioning crankcase ventilation system are listed below.
Causes of Excessive Overpressure (Pressure)


Internal engine damage/wear



Obstruction in the crankcase ventilation system



Defective pressure control valve(s)



Cylinder head cover wastegate vacuum reservoir leakage. The vacuum reservoir can also be
filled with engine oil indicating an internal leak.

Results of Excessive Overpressure


Damage to the engine oil seals



Increased engine oil consumption (can be misdiagnosed as a defective turbocharger)



Excessive engine oil in the intake system





Excessive engine oil in the charged intake tubes or the intercooler on turbocharged engines (can be
misdiagnosed as a defective turbocharger)
Engine oil dip stick is dislodged from the guide tube (if equipped)
Cause of Excessive Under-pressure (Vacuum)

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

Defective pressure control valve



Defective vacuum pump



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Cylinder head cover wastegate vacuum reservoir leakage. The vacuum reservoir can also be
filled with engine oil indicating an internal leak.

Results of Excessive Under-pressure


Damage to the engine oil seals



Increased engine oil consumption



Excessive engine oil in the intake system



Rough engine idling or engine misfire



Whistling or howling noise from the engine (can be misdiagnosed as a defective turbocharger)



Increased mixture adaptation values

N63R, N63, N63T, N74, S63 and S63T Equipped Vehicles
The crankcase ventilation system utilized in these engines cannot be measured with consistency because the
system does not incorporate a regulating valve (spring with diaphragm). The crankcase pressure is regulated by
an orifice in the crankcase ventilation tubes, and the vacuum will vary with crankcase pressure changes.
Checking the operation of this unregulated system can only be performed by visually inspecting for loose
connections or cranks in the system components. Generally active leakages will have an oily residue
surrounding that affected area. The use of a smoke machine may also be helpful when trying to locate leakages
in this system.
BXX Engines Only:
Depending on the customers driving profile, the crankcase ventilation pressure can vary when measured due to
a normal shift in the Variable Valve Lift (VVT) adaptations.
If the VVT adaptations are cleared or the vehicle has been programmed recently then the crankcase pressure
will also be adjusted because the adaptations in general have been cleared. Over time, the crankcase pressure
will change as the vehicle re-adapts to the customer driving profile. This is a not failure when the crankcase
pressure is found at the minimum or maximum limits. Do not clear any adaptations or program the vehicle for
this reason.
Attached to this Service Information bulletin is a procedure for measuring the crankcase ventilation system,
using the ISID and IMIB diagnostic equipment.

Engine Variant

Specification (mBar)
Min - Max

B38T & XB2H

15.0 - 25.0

B46

15.0 - 27.0

B48 & XB1H

15.0 - 29.0

B58

20.0 - 52.0

All Other Engines

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Specification and actual readings from the vehicle may vary by up to ±10%, but not more than 5.0 mBar.
Various measuring tools may provide results that are not within specification. All measurements below were
recorded using the IMIB. See the attachment for IMIB connection hints.
Attached to this Service Information bulletin is a procedure for measuring the crankcase ventilation system,
using the ISID and IMIB diagnostic equipment

Engine Variant

Specification (mBar)

M42, M44, M52, M52TU, S52, M54, M60, M62, M62TU, M73

16.0

M57Y

0.0 +- 1.0

S54

0.0 +- 1.0

S62

0.0 +- 1.0

S65

0.0 +- 2.0

S85

0.0 +- 1.0

S55

49.0

N47T

0.0 +- 3.0

N57T

0.0 +- 3.0

N20 and N26

35.0

N52

30.0

N51 and N52K

33.0

N52T

21.0

N54

17.0

N54T

14.0

N55

50.0 +/- 8.0

N62

22.0

N62TU

40.0

N73

30.0

WARRANTY INFORMATION
Not applicable.
Posted: Tuesday, July 17, 2018

ATTACHMENTS
View PDF attachment B110308_Attachment.
[ Copyright ©2018 BMW of North America, Inc. ]

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Attachment to SI B11 03 08

October 2013

Measuring Crankcase Pressure Using the IMIB Low-pressure Sensor Function
Preparing ISID and IMIB for Low-pressure Measurement:
1. Select “Activities”.
2. Select “Measuring Devices”.
3. Select “Measuring Device”.
4. Select “OK”.
5. Select the appropriate IMIB when the Connection Manager screen is shown.
6. Select “Set Up Connection”.
7. When the multimeter screen is shown, select “Low Pressure 1”.
8. Connect the pressure measurement hose, P/N A5E0134072, to the left port on the IMIB (1). Two
measurement hoses were shipped with the IMIB to every center. See the illustration below. Refer to SI
B04 35 09 for more information regarding the equipment shipped to all centers with the IMIB.
Port 1 = (1)
Port 2 = (2)

Attachment to SI B11 03 08

October 2013

9. Low pressure 1 (1) should be highlighted in green. Observe and record the current ambient pressure
(2).
Note: The illustration is only an example of what will be seen on the screen. This is based on
center elevation and weather patterns. This value must be recorded each time the pressure test
is conducted.

Attachment to SI B11 03 08

October 2013

Diagnostic Tool Adapter P/N 81 29 2 158 850.
The adapter will be used to adapt the 2G quick
disconnect equipment during low-pressure
measurements (up to 3 bar; see the user’s guide),
and is attached to the IMIB using the low-pressure
rubber hose (Siemens P/N A5E01034072), supplied
with the IMIB. For additional information, refer to
Service Information B04 15 10.

Attachment to SI B11 03 08

October 2013

Option 1:
Remove the quick disconnect coupler (1) from the
2G equipment 25 bar pressure transducer (2).

Install the Diagnostic Tool Adapter, P/N 81 29 2 158
850 (1), on to the quick disconnect coupler (2).

Remove the engine oil cap and install the special
pressure tester adapter, P/N 83 30 0 496 326 (1).
Connect the quick disconnect coupler (2) onto the
pressure tester adaptor. Connect the IMIB pressure
measurement hose, P/N A5E0134072 (3).
Refer to the table located on SIB 11 08 03 for
specifications.

Attachment to SI B11 03 08

October 2013

Alternative Measurement/Connection Solution
Remove the oil cap adaptor from the existing Slack
Tube Manometer.

Remove the engine oil cap and install the oil cap
adapter (1). Connect the IMIB pressure
measurement hose, P/N A5E0134072 (2).
Refer to the table located on SIB 11 08 03 for
specifications.