Golf TDI intense humming vibes, engine speed related. DMF?

[carl0s]

Hi everyone.

Before I go and order the DMF & clutch kit, does anyone have any thoughts on this?

It's my mum's car. I drove it up to my house on Friday to change the driveshafts because they were clanking like nobody's business. I don't remember noticing this noise beforehand, but I was mostly driving slowly and trying to avoid turning the wheel much due to the knackered CV joints.

I can't imagine how it could be the driveshafts causing this, given that it's clearly engine speed related even with clutch depressed, but just before I buy the DMF/clutch, I am trying to get as much community feedback as possible.

While parked, it's hard to tell if it's making the same vibes - it just sounds and feels rough as hell. I'm pretty sure it's doing the same while parked up, it's just that the interior doesn't resonate quite the same as when the car is moving.

Also, I am remembering that 6 months ago my mum brought the car to me and was complaining that every now and then it would shake violently and not go above 30mph. I have been trying to accept in my mind that this could have been limp mode due to the overboost (stuck VNT vanes, which I have since fixed).. just not limping very well. At the time I could only find a seized calliper which would obviously cause some wobbles/vibration, but overall the issue has still been a bit of a mystery but it hasn't happened since I did the calliper. There were no engine codes stored (read using VAG specific tools).

I'm kind of thinking that could have been linked to the DMF.

The DMF is bad - it'll rattle sometimes. but other times it doesn't. It's not always very noticeable over the general diesel clatter.

here's the video:



cheers

[GreenV8S]

Check the header temperatures and see whether you have a cool cylinder. If so, you may have a misfire rather than a DMF problem. That would account for the vibration and limited performance.

[carl0s]

I would have thought I'd feel a misfire, and the performance feels good.

I will check though - could save me a load of time and money.

Thanks

[GreenV8S]

carl0s said:

I would have thought I'd feel a misfire, and the performance feels good.

You said it sounds and feels rough.

[carl0s]

GreenV8S said:

You said it sounds and feels rough.

Yes but it's more of a vibration and harshness roughness. Like a bearing.

[carl0s]

I'm going to remove and inspect the flywheel. I already know it rattles sometimes though.
but I'll do that before buying the replacement.
If I find a different cause along the way, then great.

[Sensibleboy]

I doubt this is the problem but it wouldn't be the freewheeling pulley on the alternator would it? If it has seized they can result in a rattling and shudder as the engine revs drop to idle. It's the tensioner that's slapping about.

[carl0s]

Sensibleboy said:

I doubt this is the problem but it wouldn't be the freewheeling pulley on the alternator would it? If it has seized they can result in a rattling and shudder as the engine revs drop to idle. It's the tensioner that's slapping about.

Good shout, but I have tested with aux belt removed and does the same.
The one way bearing on the alternator is working OK. A little stiff maybe but seems OK.