3.0 TDI V6 Clattery when starting off

[woodss]

So I've noticed my 2009 A6 3.0 TDI V6 is pretty noisy when setting off, or when feathering the throttle at a low speed, say 30mph. It sounds like a "normal" diesel, like i'm driving a Peugeot or something.

At about 1.8k rpm (or when I put more load on the engine by adding throttle), the clattering/diesel noise stops and the car is smooth as silk with plenty of power - it sounds great. But this is now bugging me, to the point where I was worried I had no oil in it and had to check despite it just being serviced fairly recently.

It's also very very slightly hesitant when first pressing the accelerator to move off. Come to think of it, it is more pronounced when the ambient air temperature is hot - it was doing it today and it's almost 30C.

Anyone got any ideas on what the problem could be? No check engine light, no codes, no power loss...

Thank you for any help you can give.

 

[Mo-S3]

Possibly could be the timing chains.Normal for them to clatter on start up but should disappear within a 1 or 2 seconds. Your description sounds like a chain tensioner has gone or the guide could be broken as they are plastic.

 

[woodss]

It doesn't clatter on startup .. it's only when I'm at very low rpm / throttle .. think coasting along a road at 25mph in traffic with minimal throttle ... if I put the pedal down a bit more, it goes away. And similarly when I first go to pull away from a junction etc ... it's clattery until I get going.

 

[-Ju-]

So I've noticed my 2009 A6 3.0 TDI V6 is pretty noisy when setting off, or when feathering the throttle at a low speed, say 30mph. It sounds like a "normal" diesel, like i'm driving a Peugeot or something.

At about 1.8k rpm (or when I put more load on the engine by adding throttle), the clattering/diesel noise stops and the car is smooth as silk with plenty of power - it sounds great. But this is now bugging me, to the point where I was worried I had no oil in it and had to check despite it just being serviced fairly recently.

It's also very very slightly hesitant when first pressing the accelerator to move off. Come to think of it, it is more pronounced when the ambient air temperature is hot - it was doing it today and it's almost 30C.

Anyone got any ideas on what the problem could be? No check engine light, no codes, no power loss...

Thank you for any help you can give.

Sounds like it could be the egr flap in the intake.
I had the same symptoms on my SQ5 and cleaning it made a world of difference. The clatter went and pick improved no end
Fairly easy to do with the right tools.
See this thread

https://www.audi-sport.net/xf/threads/eliminate-diesel-clatter-cduc-cdud-3-0tdi.381051/

 

[woodss]

That is a really good shout. @-Ju- thanks for posting that.

Actually got out and made a quick video but the camera doesn't really pick up the sound brilliantly ...


Worth a shot though...

Also - in making that video, it wasn't doing it until the engine started getting up to temp ... when it was cold, it was smooth all the time. When it got to temp, the "clattering" started on pull away.

See what you think anyway. Maybe it'll help somebody else.

My wife has a Q7 with the 3.0 TDI and it doesn't do it at all which is why I'm wondering what's going on with mine lol

 

[-Ju-]

I know it sounds daft but mine sounded more and more like a diesel and I honestly started to dislike the car because of it, but I was convinced it didn't sound like that 18 months ago when I bought it.
It was then I spotted the linked thread and thought maybe after 37k miles it might be a little gunked up too.
An hour and a half later, i honestly couldn't believe the difference.
Its quieter, smoother and so much quicker on take off.
Give it a try, you'll be amazed whats in there!

Sent from my SM-N960F using Tapatalk

 

[woodss]

I absolutely know what you mean about the noise being too diesel-y, I agree 100%.

Fingers crossed this is what the problem is - it would certainly make sense with the symptoms I'm having.

 

[-Ju-]

I absolutely know what you mean about the noise being too diesel-y, I agree 100%.

Fingers crossed this is what the problem is - it would certainly make sense with the symptoms I'm having.

Its got to be worth a shot for free!