Emissions - Crankcase Ventilation System Info.

Emissions - Crankcase Ventilation System Info.

SI M11 07 08

Engine

March 2011

Technical Service

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

[NEW] designates changes to this revision

SUBJECT

Crankcase Ventilation System Diagnosis and Measurement

MODEL

All

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

2002-2006 Mini Cooper (R50) L4-1.6L (W10) Page 77

^ 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:

1. Preparing an engine oil cap for a crankcase pressure measurement

2. 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.

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

2002-2006 Mini Cooper (R50) L4-1.6L (W10) Page 78

2002-2006 Mini Cooper (R50) L4-1.6L (W10) Page 79

M110708_Engine_Oil_Cap_Modification

2002-2006 Mini Cooper (R50) L4-1.6L (W10) Page 80

2002-2006 Mini Cooper (R50) L4-1.6L (W10) Page 81

M110708_Measuring_Crankcase_Pressure_Using_IMIB.