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Crank Case Pressure Spec ?

Bill Owner/Technician Jackson, Michigan Posted Latest Edited

Question

Driveability

2012 Audi Q7 Elite 3.0L 8-spd—WA1LGAFE1CD004616

Chirping/Howling/Whistleing Noise At Idle

I have a noise complaint from engine area at idle that goes away if you remove the dipstick... Those of us that do Euro lines regularly my be more familiar with this sound than others.... (Too much vacuum in the crank case) I have measured the crankcase pressure at -115 mbar. I happened to have another Audi Q7 here today for service same engine code. i measured that one at -27 mbar.

My confusion started when looking up the part on WP - it shows 2 options one # states 30mbar and the other 150mabr same engine code??? I called my Audi dealer they said the valve has been updated and confirmed the part#(06E 103 547AE) for the 150mbar valve on both of the Q7's i have tested. there is a bit of labor on this engine to change it out - about 5 hours..

My question is how can the pressure be changed to 150mbar and this thing Not be houling? Currently it is making noise at 115mbar-----Has anybody ran into this issue or have known good data on the Crankcase pressure Engine code = CJWE

Chris Diagnostician

Commack, New York

Chris Default

Hello Bill, You have the 3.0l supercharged engine. The known good specs that I have are 45.5 to 48 inH20, which is about 113-119 mBar The valve you have is the updated valve. Before you tear the engine down, pop off the breather hoses from the back of the valve covers and block everything off. Measure for excess pressure in crankcase. I am seeing a trend of bad rings damaging the diaphragms…

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Steven Mechanic

Spokane, Washington

Steven Default

I see that there are 2 separate TSB's for updating the CCV valve and updating the ECM software to be compatible with the new valve. In the TSB's they say it is for "reducing" the crankcase pressure. I would get the correct part from the dealer and update the ECM. As a side note, the abbreviation of millibar is mbar. Using a capital M usually stands for Mega. I found some known good values for…

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Bill Owner/Technician

Jackson, Michigan

Bill Update

Chris and Steve thanks for your Info/Specs !! Can we agree if the whistle/howling noise goes away when pulling out dipstick it needs a crankcase pressure regulator? If so how can -115mbar be causing the noise and the updated part Audi wants to sell at 150mbar not cause noise? Is the noise from the regulator its self and not a cause of too much vacuum in the crankcase like i believe?

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Jim Owner/Technician

Charlotte, North Carolina

Jim Default

Is the noise coming from the CCV valve or the rear main seal?

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Joel Diagnostician

Soquel, California

Joel Default

I have taken the sample from oil dip stick only, I have seen some of then the needle stay below -10 inches of water on good systems while other good fluctuates in between +10-10. if you have a whistle the needdle on my gauge exeed the -30 inh02, This is the only tool I used, is the gauge fron the evap machine red line if you plugg de air port now you can read crancase pressure .

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Bill Owner/Technician

Jackson, Michigan

Bill Update

CORRECT CRANKCASE PRESSURE SPEC ON CJWE = 30 mbar. watch out for the different part numbers and Audi catalog issues..... Audi dealer/catalog will sell you part # 06E 103 547 AE (150mbar) for this VIN # --- IT IS INCORRECT! Original part number found on valve after disassembly was 06E 103 547 F -- transfers to 06E 103 547 AC (30mbar) I have replaced the part crankcase pressure is now at…

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Gabriel Owner/Technician

Hialeah, Florida

Gabriel Default

This EXACT problem happened to me with a 2011 S5. I had to pull the intake again, and replace the valve with the correct part number! BEWARE BEWARE BEWARE.

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