wanamees

Problem: Light but noticable vibration on idle, when in drive or reverse. No vibration when in park or neutral.
It's like R4 diesel engine type of vibration - some times its very light and sometimes more noticable. It becomes more noticable when playing with brake and driving/reversing car inch by inch.

I went to mechanic today and unfortunately they only had an hour of time so they could not find the problem.
They looked through engine and axles (as I was thinking of gearbox mounts).
They found 1 faulty engine mount (front) and few other minor faults not related to engine.

I don't think this vibration is caused by this one half faulty engine mount...

Next week I will see electritian - maybe coils gone bad or something else?

Any ideas? Thanks in advance.

Car was serviced just few monts and some hundred kilometers ago.
Lot of other things like all rollers on serpent belt, power steering pump, alternator were replaced - but I cant see any connectedness here.

wanamees

I can't change previous post?

It's 2004 A8L 4.2 petrol engine.

mishar

Welcome to the board! I would suggest that you start with the sticky.

wanamees

Thank you. I apologize.
Read through the sticky and updated my profile.

I have already searched this forum and googled around a lot - I have found many topics about engine vibration and few with some similarities, but none exactly with same issue.

I'm getting vag-com in few days to see, if there are any faults - few months ago there were 0 faults!

MP4.2+6.0

it can set up some vibration from my own experience with both my C5 A6 4.2 and my D3 W12. Both had bad torque mounts over the years; caught the (major job) W12 one under CPO warranty. Had some vibration in 4.2 for a long time before I finally realized the mount was broken when I pulled the cylinder head one time and then was looking almost right at it.

Because that mount is purely mechanical in nature--no solenoid switching--you won't find any codes for it either, whether old or new. It is relatively far forward on the (North America) passenger side of the motor. If you see either a crack running around the rubber area or brown oil stains coming out or below it, it is gone. Car as two primary motor mounts that are the solenoid controlled ones with the oil dampening, but then this one that resists torsional forces. It has the oil in it too, but no solenoid. Also can then connect to why you feel it more in gear (when those forces come into play) than in park or neutral.

mishar

As MP said, but wait for the scan. Misfire would also produce more pronounced shaking in a gear than on just idle.

MP4.2+6.0

...though I would expect a CEL in that case.

mishar

You are right, but in "online repairs" you never have a whole picture and what you have is already interpretation.

wanamees

You are refferring to "rubber bush" #14 on picture as torque mount?
AUDI A8 [A8] (EUROPE) 2004: ENGINE: 19910. SECURING PARTS FOR ENGINE
As it has also 2 engine mounts on bottom - I'm not sure wich one of them is broken (leaking oil) on my car - they just said front one - I will specify it and replace as soon as possible.

I have not had Chekc Engine Light never on this car! It doesn't matter if i but pedal to metal or just cruise around.

I will get VAG hopefully today to check any faults

wanamees

Ok, got my ebay vag-com working (no need for real thing at this time).

1) Contacted the car servide - they said yes, the "torque mount" is leaking.
2) Got 2 errors from engine - they came back after deleting (and driving).These should be both left and right engine mount solenoids... meaning both engine mount solenoids are gone bad, wiring gone bad? Because bottom motor mounts are not leaking and hopefully shouldnt replace them entirely.

No misfire or anything else detected.