Good morning, my 2011 Octavia 2.0 TDI  occasionally shuts down in a rough way. More vibration, louder - a rough clanky noise-, and quite abrupt. It doesn't happen all the time. It's done 180k.

Yesterday after pulling away there was a unpleasant noise from the engine when pulling away just after starting and some juddering. After pulling over and having a quick check, that nothing obvious was amiss I drove for 2 or 3 minutes and the issue had gone. Same thing happened from cold start later in the day.

Any pearls of wisdom? Thanks.

DMF failing?

I'm not sure if your engine is PD or CR at that manufacture year, but I assume that the CR has an anti-shudder valve too? If it does, I'd be looking at that as a starting point. My 2.0 PD shudder valve died but it did throw up a CEL. The shutdown then, was very typically agricultural diesel instead of a smooth stop.

Dual mass flywheel I'm afraid.

 

If the fault only manifested itself at shutdown & its a CR engine then it could be the throttle valve (as they are called on those vehicles) coked up & not able to shut properly, mine had that problem & I was very relieved to find that it was not the DMF.

 

I did a clutch & DMF change a year later, at 95K miles it was worn but still reasonably serviceable, after the remap the engine would pull much higher revs but was very clattery in that higher range, the new DMF silenced it.

On reflection if the throttle valve is sticking or the plastic gears have stripped then it could explain your other 2 oddities.

Thank you for the replies.

The shutdown has been noisy on off for about 1 year, sometimes happening every shutdown for a week then not happening for a month before reappearing. The shudder and clatter when I pull away only started a week ago. I'm surprised it's not around all the time. It only happens for the first couple of gear changes from cold, after that the everything seems normal. M25 driving. Speed limit to mile after mile of stop start, every day. I would have thought it would happen every time I pull away?

Hello! 
 

I would try to provoke the symptoms by slowly pressing and depressing the clutch in neutral and 1st/2nd gear. You can also listen to the engine/flywheel area while starting/stopping the engine in neutral both with the clutch pressed in and released. 
 

These tests should be able to give you an idea if the sounds come from the dual mass flywheel or not, but you may have to seek out an experienced ear. 
 

When slowly engaging the clutch in neutral there is not a lot of resistance for the flywheel, so if it is very worn you could be able to hear some clattering.

 

I had a bad clattering sound when doing this, and it went away with a new DMF. 
 

I also felt that the clutch pedal was kicking back when starting up in a steep hill. That is also gone with a new DMF… you could try that as well 

 

Keep in mind that a DMF’s nature is a bit «wobbly» in order to absorb the vibrations from the engine on lower RPMs… 

 

good luck!