Crankcase Ventilation System Diagnosis And Measurement (M11 07 08)

Publication date: 2015-03-01
Reference number: M11 07 08

CRANKCASE VENTILATION SYSTEM DIAGNOSIS AND MEASUREMENT

TECHNICAL SERVICE BULLETIN

Reference Number(s): SI M11 07 08, Date of Issue: March 2015

MINI:	All Models
GROUP:	Engine

Superceded Bulletin(s): SI M11 07 08, Date of Issue: March 2011

This Service Information bulletin supersedes SI M11 07 08 dated March 2011.

SUBJECT

Crankcase Ventilation System Diagnosis and Measurement

INFORMATION

All current MINI 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 (underpressure) 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

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 Underpressure (Vacuum)

Defective pressure control valve

Results of Excessive Underpressure

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

Attached to this Service Information bulletin are two procedures:

Preparing an engine oil cap for a crankcase pressure measurement
Measuring the crankcase ventilation system using the ISID and IMIB diagnostic equipment

Specification and actual readings from the vehicle may vary by up to ±10%, but not more than 4.0 mBar.

Engine Variant	Specification (mBar)
W10	1.0-6.0
W11	2.5-4.0
N12	22
N14	38
N16	36
N18	36
B38	50
B48	50

WARRANTY INFORMATION

This service information bulletin is intended to provide technical diagnostic and/or repair information.

Claims that result from the repair of a verified defect are to be processed following established warranty policies and procedures.

ATTACHMENTS

M110708_Engine_Oil_Cap_Modification

M110708_Measuring_Crankcase_Pressure_Using_IMI