Judder when idling

[Tomyates]

Hi all,
Iam experience a really annoying judder/shake/knocking 😂 when idling... the revs don’t fluctuate it sits where it should and the judder goes away as soon as you give it a slight rev... still drives spot on... I’ve been told it’s unlikely to be the dog bone mount and it’s unlikely to be the DMF... maybe an air leak?? Someone suggest unplugging the MAF sensor and seeing what it runs like?

[Little Pete]

What vehicle is it?

[Tomyates]

Oh yes sorry... it’s a 2006 Audi A3 TDI

[Little Pete]

It’s very unlikely the dog bone mount as you call it would cause a judder on idle even if it was FUBAR. Is the EML lit? Does the judder/knock alter when you press the clutch pedal? If it is the DMF -quite common-you can generally feel the judder through the pedal as the clamping force on the flywheel changes.

[Tomyates]

There is no lights lit at all... which is why I’m confused... I haven’t noticed it change when I dip the clutch, I only notice it when you give it a slight rev... I think the thrust bearing is making a slight noise... only slight though

[ToothbrushMan]

if you get a noise/judder at idle then ;-

when clutch pedal is up = worn release bearing
when clutch pedal is down = could be worn input shaft bearing

[GreenV8S]

If it's speed related and does not seem to be associated with the clutch or any misfire, it might be worth looking for something resonating. For example if you have lost an exhaust hanger or got severe corrosion, you might find the exhaust resonates at certain speeds - it might even knock on something. Time to listen from outside and see if you can locate the source.

[Tomyates]

That could make sense actually... when it was as making a noise I Stuck my head out of the car and looked underneath and it sounding like it was coming from the area that the down pipe meets the Straight pipe... if that makes sense? Although i think the thrust bearing makes a slight noise when you push the clutch... so I’m not sure

[Tomyates]

I popped it to the garage quick on my way home and there first answer was It’s the start of the DMF Failing....

[stevensdrs]

Well the garage would say that. It is a common fault with these cars but I would seek a second opinion before parting with a grand to fix it.

[Tomyates]

I thought exactly that, yeah absolutely I will, is £1000 a rough cost for replacement is it?

[stevensdrs]

Tomyates said:

I thought exactly that, yeah absolutely I will, is £1000 a rough cost for replacement is it?

From a main dealer it will likely be around that figure.

[Tomyates]

Wow.... the DMF it’s self is about £300 isn’t it? For a decent one

[Little Pete]

stevensdrs said:

Well the garage would say that. It is a common fault with these cars but I would seek a second opinion before parting with a grand to fix it.

They would say that if it was the DMF failing.

[Krikkit]

Tomyates said:

Wow.... the DMF it’s self is about £300 isn’t it? For a decent one

Yep, but don't forget that you wouldn't just replace the DMF.

£315 for a DMF, £204 for a clutch kit, £30 for the concentric slave, maybe another £50 for the oil seals in the area if you want to do a decent job, then removal and refit of the gearbox will be a few hours work.

[Tomyates]

Yeah absolutely... am I right in thinking a clutch all in is about £750...? With the DMF Aswell it’s gonna be he best part of £1000 isn’t it really... ughhh

[Tomyates]

I’ve had a quote off one of my local... £670 all in clutch and DMF and that’s using LUK parts