Mk5 GT TDI 140 engine shudder at idle

**Crasher** · 27-07-2010,08:36 AM

The belt tensioner moving around violently is an indication of a failed alternator pulley one way clutch.

**anmover** · 27-07-2010,02:45 PM

Ive got a similar problem now on my 04 tdi, the engine is sometimes very rough when idling. Also at 25-30mph it feels like its losing power for a split second every few seconds. I've had the car for 2years and its only done 46k, i've had vw service it twice now and both times theyve found nothing wrong with it!

**markyd85** · 27-07-2010,10:08 PM

My alternator pulley has been replaced within the last 12 months, but still the tensioner hammers, this only happens when really warm sitting in traffic jams for instance.

**Crasher** · 28-07-2010,01:17 PM

It would have the new pulley checked.

**VW_GTTDI** · 17-09-2010,09:52 PM

Ive had my car for almost 3 years and mines judders when idle ever since..... sometimes constant...sometimes intermittent...sometimes even violently! ive had diagnostics and spent hours searching through forums to no avail, people claiming it to be this, that and the other! One thing i can say is that it has never affected the drive at all, my car drives like a dream no misfiring at certain revs, no loss of power or anything at all.

So matey's just let it be!

**markyd85** · 01-03-2011,07:30 PM

I had my alternator tensioner replaced today. Definitely rule that one out, still the same judder when warm. Thats £80 down the pan.

**martynah** · 01-03-2011,10:01 PM

Crasher was spot on - injector failure , hit me on the m4 near
Bristol in December, injector no 4 had failed and shorted out the electrics.

Completely cut out and wouldn't restart.

If you don't fancy a huge bill consider Vw extended
Warranty i got roadside Vw tech diagnosed it then towed
Home and to dealer plus 100 gbp excess got me home
And covered 1500 GBP repairs - 380 GBP a year Inc roadside

Best news of all is that the judder is cured 8-)

**harltech** · 01-03-2011,10:21 PM

I have worked on VAG cars for 10years and have never seen a TDI that idles smooth. they all seem to be a bit lumpy at idle.

I have a mate that works for skoda and he recons they have started putting soild flywheels into taxis with TDI engines and it makes them smoother and more reliable. Although I can not validate this as I have never fitted one myself.

**Crasher** · 02-03-2011,12:18 AM

Originally Posted by markyd85

I had my alternator tensioner replaced today. Definitely rule that one out, still the same judder when warm. Thats £80 down the pan.

It was probably not the tensioner; it is the one way clutch alternator pulley which makes the belt and tensioner flap.

**markyd85** · 03-03-2011,07:51 PM

Crasher, i had this problem before the clutch pulley was replaced and it continued after it was replaced so unless the clutch pulley is faulty in some way i find it hard to see it's this.

I took it to the local vw specialist and he said exactly the same thing as you, the clutch pulley. I told him this had been replaced, he didnt have anymore suggestions. It's been like this for best part of 18 months so im not too bothered, i've done 25k since ive had the car and ever since this judder when idling warm has always been there.

Thanks for the suggestions though.