Knocking and shuddering diesel

Argo foc yourself

I have a 2014 Skoda octavia
COM ELEGANCE 2.0 TDI 150HP 4DR Euro 5
Engine Capacity 1968


When the engine is cold the car will shudder a little for the first 500 meters. Once it heats up it is fine and no shuddering. Also, during this first 500 meters I can often get a knocking noise from the engine - about 3 knocks in quick succession and then no more after that.

Any ideas? It has just been serviced. Also really hard for the mechanic to experience this as by the time the car gets to garage it has heated up!

DPolo

Is the car manual or automatic/DSG?

If it's a manual it sounds like flywheel is on it's way out, just from personal experience with VAG TDI cars I've owned with similar symptoms.

Argo foc yourself

DPolo wrote: »

Is the car manual or automatic/DSG?

If it's a manual it sounds like flywheel is on it's way out, just from personal experience with VAG TDI cars I've owned with similar symptoms.

manual.. would flywheel account for knocking or shuddering or both?

Just trying to build a profile to suggest to mechanic

DPolo

It would be the shuddering/juddering when setting off , the knocking could be anything from a clutch release bearing to an engine mount knocking.
Does the clutch pedal feel heavier/notchier than usual ?

Unfortunately if it is the flywheel it can be anywhere from €800-1200 to replace depending on labour and that

mickdw

Argo foc yourself wrote: »

I have a 2014 Skoda octavia
COM ELEGANCE 2.0 TDI 150HP 4DR Euro 5
Engine Capacity 1968


When the engine is cold the car will shudder a little for the first 500 meters. Once it heats up it is fine and no shuddering. Also, during this first 500 meters I can often get a knocking noise from the engine - about 3 knocks in quick succession and then no more after that.

Any ideas? It has just been serviced. Also really hard for the mechanic to experience this as by the time the car gets to garage it has heated up!

Any change in the knocking sound when stationary if you press / release clutch pedal?

You could also drop car to mechanic last thing in evening and let him check it in the morning when cold.

Argo foc yourself

DPolo wrote: »

It would be the shuddering/juddering when setting off , the knocking could be anything from a clutch release bearing to an engine mount knocking.
Does the clutch pedal feel heavier/notchier than usual ?

Unfortunately if it is the flywheel it can be anywhere from €800-1200 to replace depending on labour and that

clutch feels fine.

yeah the shuddering/juddering is only when setting off

Argo foc yourself

mickdw wrote: »

Any change in the knocking sound when stationary if you press / release clutch pedal?
.

generally only happens when I start off after and for a couple of seconds and gone again. Never happens when stationary regardless of release cluth pedal

newmember2

If the juddering is happening when pulling away/engaging the clutch then it's your flywheel or clutch or possibly both.

DPolo

Argo foc yourself wrote: »

clutch feels fine.

yeah the shuddering/juddering is only when setting off

It's definitely pointing towards the flywheel on its way

Argo foc yourself

DPolo wrote: »

It's definitely pointing towards the flywheel on its way

pants!!! and is it something that should be done or just wait for it to go? Basically I am asking if it is like timing belt and would cause further damage

DPolo

Argo foc yourself wrote: »

pants!!! and is it something that should be done or just wait for it to go? Basically I am asking if it is like timing belt and would cause further damage

Worst case scenario is breakdown at side of road, the extra cost and time of getting car recovered and fixed. Either way not cheap to replace because of DMF set up on them as below

Usually dual mass flywheels used in the 2.0 TDI drivetrains (open to correction on that, my 08 A4 was dual mass) which tend to be a bit weak to any kind of abuse like stop start traffic or heavy starts. If it needs replacement opt for a single mass flywheel if possible , it'll be cheaper and longer lasting I found

Edit: as Irish Steve said below it could be a relatively cheap fix, difficult to tell without actually seeing the car, best to bring it in to your mechanic to be on safe side whenever you have a chance

Irish Steve

If only when cold and for a very short time, I'd be more inclined to check the heater plugs first before looking to spend a lot of money on flywheels etc. Different engine, the Renault Kangoo was notorious for not even starting when more than one plug had failed, if the DMF was that bad, it would knock bang and rattle regardless of the engine temperature, whereas a failed heater plug can significantly affect how well the engine runs for a few seconds, in that having started, most modern diesels keep the heater plugs active for a while, until there's a bit of heat in the block. That could also explain the "knock" that you mention, one cylinder is having to ignite and work with colder air/diesel mix.

Having said that, if the engine is indeed running rough, a DMF that's on the way out could be rattling as a result, but the underlying issue may be resolved for quite some time by just replacing any failed heater plugs, which should not be a massive or expensive job.

Argo foc yourself

thanks everyone - have a few bits now to go to garage with