Strange idle shimmy - 3.0 6spd Guru's needed please!

[fastsoup]

Hi Guys,

I have searched top to bottom for any information regarding my issue and have not found a thing, and I am hoping the B6 Guru's can chime in and help me out.

2005 Audi A4 3.0 Quattro with 6spd manual. Timing belt, water pump, plugs, valve cover all replaced this past winter.

At idle, only when the vehicle comes to normal operating temperature, do I notice a shimmy in the car. The RPM gauge remains perfect with no fluctuation at all. I replaced PCV valve and ensured all my vacuum lines were intact and no leaks anywhere. I have read that it may be a flywheel issue but it can't be because if it was mechanically, it would happen all the time. Now here's the kicker, if the vehicle reaches normal op temperature and the shimmy is present, all I have to do is turn on the A/C and the shimmy goes away entirely, or lessens to a degree where an average person can't feel it. As soon as I turn the A/C off, shimmy comes right back. Turning the A/C on has no visible fluctuation in the RPM needle; it remains constant.

I don't want to keep chasing this and throwing money at it in hopes of getting somewhere. VAGCOM scan displayed no issues or fault codes. Live monitor of the system at idle came back clean. No engine lights present, and the vehicle drives beautifully. Is this a common or know issue among the B6 3.0?

Thank you

[a4audi4fun]

Have you checked engine mounts?

[SJorge3442]

Have you checked engine mounts?

This. I bet something is off with a mount somewhere. Maybe the front snub mount, maybe the engine mounts, or the transmission mount.

[fastsoup]

This. I bet something is off with a mount somewhere. Maybe the front snub mount, maybe the engine mounts, or the transmission mount.

No I haven't. With the fact that it only happens warm I never thought to check. Ok, I will look at that today and reply back.

Thanks guys

[19jdog]

Have you checked engine mounts?

This +2 whats the millage, have the motor mounts been changed before??

[fastsoup]

This +2 whats the millage, have the motor mounts been changed before??

So I put the car on a hoist at work, warmed the engine up till the shaking began, and then jacked the engine up via oil pan. Only thing I noticed is the vibrating getting worse as I raised the engine. I could not find a sweet spot where the vibration subsided. I don't really want to spend money on 3 mounts and be back to square one. Does anyone have a better way of testing the mounts to see if they are my issue?

Thanks

[imnuts]

You could just loosen them, then realign them. How old are the mounts in question? Odds are that if you don't know, they probably need replaced.

Sent from my DROID Turbo 2

[19jdog]

So I put the car on a hoist at work, warmed the engine up till the shaking began, and then jacked the engine up via oil pan.

Something tell me lifting the engine via the oil pan is NOT a good idea.

You could just loosen them, then realign them. How old are the mounts in question? Odds are that if you don't know, they probably need replaced.


Sent from my DROID Turbo 2

Change all 4 (3 for the motor one on the transmission), and see if it improves. Seems like you have access to a lift. I changed mine when I pulled the motor. 034 street ftw

[fastsoup]

Something tell me lifting the engine via the oil pan is NOT a good idea.





Change all 4 (3 for the motor one on the transmission), and see if it improves. Seems like you have access to a lift. I changed mine when I pulled the motor. 034 street ftw

Ok, So I replaced both side engine mounts, front snub mount, and transmission mount...concern is still present

I was speaking with a local INDY mechanic and he maid mention of the camshaft actuator on the drivers bank. Apparently this causes the cams to be out of line below 1500rpm and could cause a shake, and even a random misfire at times (which I still occasionally get). Anyone have any experience with camshaft actuator?

I am ready to go back to BMW! I was always told that VW products were built extremely well, but also extremely finicky.

Help!

[SJorge3442]

Ok, So I replaced both side engine mounts, front snub mount, and transmission mount...concern is still present

I was speaking with a local INDY mechanic and he maid mention of the camshaft actuator on the drivers bank. Apparently this causes the cams to be out of line below 1500rpm and could cause a shake, and even a random misfire at times (which I still occasionally get). Anyone have any experience with camshaft actuator?

I am ready to go back to BMW! I was always told that VW products were built extremely well, but also extremely finicky.

Help!

By actuator, I assume he means the VVT mechanism. I've personally never heard of anyone replacing them. You should get a code for cam position being off. There are also the normal cam position sensors at the back of the heads which just read the positions of the cams relative to the rest of the engine. I believe you can unplug all of the VVT actuators and not have any issues, but you will lose top end HP. It could be possible that the cam is locked in the high RPM range and cant return to the idle range. Again, this should still throw a cam position code.

[fastsoup]

By actuator, I assume he means the VVT mechanism. I've personally never heard of anyone replacing them. You should get a code for cam position being off. There are also the normal cam position sensors at the back of the heads which just read the positions of the cams relative to the rest of the engine. I believe you can unplug all of the VVT actuators and not have any issues, but you will lose top end HP. It could be possible that the cam is locked in the high RPM range and cant return to the idle range. Again, this should still throw a cam position code.

At the back of the valve is where the camshaft actuator sits. I have absolutely no codes other than my mysterious random cylinder misfire.

Could my timing be off? Belt was done before I purchased it.

[SJorge3442]

At the back of the valve is where the camshaft actuator sits. I have absolutely no codes other than my mysterious random cylinder misfire.

Could my timing be off? Belt was done before I purchased it.

Its a strong possibility timing is off. Its possible to check the cam timing via VCDS, but Im unfamiliar with what values you need to look at.

[road_tripper]

I'll go out on a limb and say it is your power steering pump.

[diagnosticator]

There was a TSB issued for engine vibration with the A/C compressor loaded. Has something to do with the compressor mounting bracket.

[road_tripper]

There was a TSB issued for engine vibration with the A/C compressor loaded. Has something to do with the compressor mounting bracket.

here's a link to the tsb

[imnuts]

There was a TSB issued for engine vibration with the A/C compressor loaded. Has something to do with the compressor mounting bracket.

here's a link to the tsb

Never realized there was a TSB for this. I have it occasionally to, but never bothered with it. Time to read over the doc and see when I can try that out myself.

Sent from my DROID Turbo 2