Audi A6 2.0 tdi Auto Engine Vibration etc

[imastu pidgit]

Just developed a fault today - symptoms are:

- a vibration, almost a shaking, of the engine (bonnet open) when stationary;
- the vibration comes through the pedals and the steering wheel;
- worst at low speeds and setting off;
- a tapping sound from the bonnet when driving at all speeds;
- it feels like the level of vibration reduces after a while, but that could be wishful thinking;
- no loss of power;
- no warning lights;

Having trawled the forum and google, it sounds like it could be anything from the dual mass flywheel, the entire engine, the timing belt (which I have just had replaced).

Before the obligatory trip to get fleeced, does anyone have any suggestions of what the problem is?

[a8 tech]

You do not have a dmf, check mvb group 04 zone 4 to check the timing has been correctly set in address 01 value should be -2.5 to +2.5

Drain the fuel filter and check for excess soot content in the fuel

check fuel quantity at idle mvb 01 group 02, range 4.5mg/h to 9mg/h

run basic setting of egr channel 03

EGR active and EGR inactive should differ by
at least 120 mg/stroke

Check for excess black smoke, possible tapping caused by exhaust gas leak at the egr cooler pipe or hairline split at the inter cooler (whooshing noise)

Also the egr valve port flap breaks away from the spindle

Other tapping related noises caused by air con compressor pulley failure.

The information given allows you establish uneven idle causes and I would question the possible link to the cambelt change, I see lots of issues with the valve timing due to incorrectly aligned pulleys or incorrectly tensioned cambelts

[imastu pidgit]

Because it's an automatic? Ah, my technical knowledge...

Thanks for the quick response - I will admit to not knowing much about the other first few suggestions either, and will probably have to take it to my local independent (Fontain) for a fix. Just odd that it suddenly came from nothing - had just driven about a mile, I stopped and switched off, started it again a few minutes later and it happened suddenly while pulling away.

But to the extent that I now know it's not necessarily going to be the horrible expense of a DMF replacement, I'm comforted...

[a8 tech]

There is a type of dmf fitted to the multitronic but its only real fault is harsh noise from cranking

I suggest you seek a dealer as there are so many threads that start with

been to local garage, fitted x,y,z then took it to dealer after they couldn't fix !!!!!!!!!!!!!!!

Dealer found x, y and z not required but needs !!!!!!!!!!!

Save yourself the hassle and expense, Audi dealers are after all are supported by the manufacturer

Good luck

[imastu pidgit]

Many thanks - to be fair to them they are an Audi specialist, albeit independent. And I've not always read flattering things about Audi main dealers on here, in terms of both technical expertise and price.

I'll post how I get on, assuming I still have a home to live in after the bill...

[imastu pidgit]

This has just got very serious - I am being told a piece of one of the pistons has broken off and the bore has been scored. Upshot is a new engine.

Does anyone have an idea how much we're talking - 2.0 tdi, either new or remanufactured, or used?

Edit -see quotes on ebay and elsewhere for £1,200 to £1,600 fitted, with all sorts of caveats. Add in the full cost of putting the car back together, profit margins to the repairer etc, would I see anything left from £4k?

[Guest 2]

Sorry to hear that mate. Hope you get it sorted, was your car serviced to the schedule? Do they know how and why the piston broke and caused the damage?

Chris

[imastu pidgit]

No, they spent enough time and money working out what the problem was, I didn't really want to know why as well...

I bought it in November 2010 - 2 and a half years old with 88k miles on it, which to me said it had just done a lot of motorway mileage and should be in good shape. Car supermarket, partly to get a choice, partly to ensure a part-ex on my not-much-wanted 10 year old BMW 540 touring. Limited service information, but it was last serviced a year and 29k miles previously.

The BMW was great until bits started to go wrong, plus in the current oil price environment and now driving to work every day, I really wanted to do a bit better than 18mpg - hence my first diesil. I thought diesils were supposed to be good for 200k+ miles, ergo the purchase for what was an apparently good price - now I know why...

As said earlier, I immediately had it full serviced and the cambelt changed, asked them to look at everything and tell me what they thought - with a positive report, I thought it worth not taking a warranty. False economy...

Not a bad idea on the letter - nothing to lose.