Strange noise
#1
AudiWorld Senior Member
Thread Starter
Strange noise
the hard part is to describe the noise. It's sort of like a soft honk of a Canadian goose without "H" of the "K" ooon, ooon. It is not very loud and seems to be coming from the front passenger side. It is noticeable when starting out from a stop under gentle to moderate acceleration. I can duplicate it at any speed from 10 to 50 by slightly increasing pedal pressure. If I let up, the noise stops. Frequency between the "ooon ooon" increases with more acceleration. With heavier (not pedal to the metal) acceleration, it seems to be constant. oooooooooooooooonnnnn but it is not very loud and other noises make it difficult to hear. At first, I thought it was coming from a revolving wheel or rotor but it does not increase (time between ooon, ooon) with speed. The only thing that makes it more pronounced or rapidly repeating, is acceleration regardless whether from 0-10 mph or 40-50 mph.
Would love to record the noise and post an audio file but don't know how to do that. I could record it with my smart phone with a "voice recorder" app but I'm not sure if it would pick the sound over road noise.
Taking a shot that this might recognizable by someone else. I realize this is a long shot.
Would love to record the noise and post an audio file but don't know how to do that. I could record it with my smart phone with a "voice recorder" app but I'm not sure if it would pick the sound over road noise.
Taking a shot that this might recognizable by someone else. I realize this is a long shot.
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faisalfaisal (09-06-2023)
#3
AudiWorld Super User
I'm thinking this was maybe one of the descriptions for the 4.2 world's most expensive PCV valve acting up. Does that ring a bell with anyone?
Meanwhile, your description may be tied to motor running conditions where the vacuum level is dropping as you push on the gas pedal, and why it can occur over a range of speeds. Could also fit PCV valve operation--the flat topped black plastic circular part several inches in diameter toward the back of the motor high up with two connected hoses on the underside. There is also the little known suck pump--basically an in line Y connector (it is NOT a pump even though often called that for some reason in Audi parts slang) in large diameter vacuum related hoses that has a one way check valve plastic ball bearing sort of thing inside it. On my C5 4.2 that was back by the firewall near the master brake cylinder. My W12 has one too, where it is close in the the rubber intake hose fitting between the MAF and the throttle body.
Meanwhile, your description may be tied to motor running conditions where the vacuum level is dropping as you push on the gas pedal, and why it can occur over a range of speeds. Could also fit PCV valve operation--the flat topped black plastic circular part several inches in diameter toward the back of the motor high up with two connected hoses on the underside. There is also the little known suck pump--basically an in line Y connector (it is NOT a pump even though often called that for some reason in Audi parts slang) in large diameter vacuum related hoses that has a one way check valve plastic ball bearing sort of thing inside it. On my C5 4.2 that was back by the firewall near the master brake cylinder. My W12 has one too, where it is close in the the rubber intake hose fitting between the MAF and the throttle body.
Last edited by MP4.2+6.0; 08-27-2015 at 03:47 PM.
#4
AudiWorld Member
Is this the sound?
Here is a possible fix without replacement.
Audi Addict ? PCV "hunting" noise - solved...after 2 years
Last edited by sbcrazy; 08-27-2015 at 03:54 PM.
#7
AudiWorld Senior Member
Thread Starter
I see what you mean about world's most expensive PVC valve. I see products ranging from a Viaco product selling for $28.00 to $135. However, the Viaco does't look the same as the "genuine OEM" on this site:
05 2005 Audi A8 Quattro Crankcase Vent Valve - Engine Mechanical - Beck Arnley, Genuine, Vaico - PartsGeek
Then I found one on ebay for really cheap $17.59 that looks right but the compatibility says it's not right for 2005 A8.
http://www.ebay.com/itm/New-4-2L-Engines-Crankcase-Vent-Valve-For-Audi-Volkswagen-077103245B-/181329272632?fits=Make%3AAudi&hash=item2a38111f38&vxp=mtr
Ironically, there's one that says it's compatible with 2005 A8, but it doesn't look the same. It looks liike the Viaco and it's also cheap. $19.
http://www.ebay.com/itm/New-Engine-Crankcase-Vent-Exhaust-Valve-Audi-06C103245-/291142603433?fits=Make%3AAudi&hash=item43c97392a9&vxp=mtr
What am I missing and will the cheap part not work or be too low quality?
http://www.ebay.com/itm/New-Engine-Crankcase-Vent-Exhaust-Valve-Audi-06C103245-/291142603433?fits=Make%3AAudi&hash=item43c97392a9&vxp=mtr
05 2005 Audi A8 Quattro Crankcase Vent Valve - Engine Mechanical - Beck Arnley, Genuine, Vaico - PartsGeek
Then I found one on ebay for really cheap $17.59 that looks right but the compatibility says it's not right for 2005 A8.
http://www.ebay.com/itm/New-4-2L-Engines-Crankcase-Vent-Valve-For-Audi-Volkswagen-077103245B-/181329272632?fits=Make%3AAudi&hash=item2a38111f38&vxp=mtr
Ironically, there's one that says it's compatible with 2005 A8, but it doesn't look the same. It looks liike the Viaco and it's also cheap. $19.
http://www.ebay.com/itm/New-Engine-Crankcase-Vent-Exhaust-Valve-Audi-06C103245-/291142603433?fits=Make%3AAudi&hash=item43c97392a9&vxp=mtr
What am I missing and will the cheap part not work or be too low quality?
http://www.ebay.com/itm/New-Engine-Crankcase-Vent-Exhaust-Valve-Audi-06C103245-/291142603433?fits=Make%3AAudi&hash=item43c97392a9&vxp=mtr
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#8
AudiWorld Member
Amazon.com: B777 077103245B 00-08 Audi Crankcase Vent Valve A6 Quattro S4 S8 00 01 02 03 04 05 06 07 08: Automotive
Read the reviews and that might help
#9
AudiWorld Senior Member
I replaced mine with the Vaico
the hard part is to describe the noise. It's sort of like a soft honk of a Canadian goose without "H" of the "K" ooon, ooon. It is not very loud and seems to be coming from the front passenger side. It is noticeable when starting out from a stop under gentle to moderate acceleration. I can duplicate it at any speed from 10 to 50 by slightly increasing pedal pressure. If I let up, the noise stops. Frequency between the "ooon ooon" increases with more acceleration. With heavier (not pedal to the metal) acceleration, it seems to be constant. oooooooooooooooonnnnn but it is not very loud and other noises make it difficult to hear. At first, I thought it was coming from a revolving wheel or rotor but it does not increase (time between ooon, ooon) with speed. The only thing that makes it more pronounced or rapidly repeating, is acceleration regardless whether from 0-10 mph or 40-50 mph.
Would love to record the noise and post an audio file but don't know how to do that. I could record it with my smart phone with a "voice recorder" app but I'm not sure if it would pick the sound over road noise.
Taking a shot that this might recognizable by someone else. I realize this is a long shot.
Would love to record the noise and post an audio file but don't know how to do that. I could record it with my smart phone with a "voice recorder" app but I'm not sure if it would pick the sound over road noise.
Taking a shot that this might recognizable by someone else. I realize this is a long shot.
It was not acting up, but at 75,000 miles and 10 years it was a good 20.00 expense.
Replaced the one on my 2006 XJR. These have so much in common, aluminum body, air struts, 6 speed ZF, 4.2 liter engines, and the same looking PVC or crankcase vent valve.
#10
AudiWorld Super User
So I pulled 077103245B as the part # from Euro EKTA for a 2005 4.2. Audi - A8Q - 2005 - Engine, Clutch Teile Katalog (Pats Catalog) That seems to be the part # right on the one from Amazon that you can make out in the picture for $36. You can type part # in Google, but a quick scan of hits and that one seemed very good for supposed OE/OES. AudiUSAParts (on line discount dealer) is just over $100, confirming the usual world's most expensive PCV.