I've got a 'knocking noise'!

[Geffix]

Hello and help.  I have a 2016 Citigo Colour Edition 30,000mls.  I'm hearing a knocking noise from the engine area when starting off or travelling at low speeds, under low power in second gear.  The local dealer after a £75.00 fee came up with the 'probable' cause as the pre dampers on the clutch plate.  Another garage believed the cause is the dual mass flywheel.  Either way its an expensive fix.  Does anyone have thoughts as to a probable cause?

Help/ideas appreciated

[freemansteve]

Does a Citigo even have a dual-mass flywheel? I really don't know, but they are common on larger diesels...

 

The explanations you have been given don't stack up to me... Why only 2nd gear or low power if there were a clutch or flywheel problem?

[Boro8688]

As mentioned above, It wont be the dual mass fly wheel (DMF) as no citigo has one fitted. so it rules that out as the problem  Citigo's do have a clicking noise when operating clutch from engine/gearbox area but this isn't a fault. It does seem strange that its happening only in 2nd gear. 

 

[Geffix]

Thanks for your comments.  I had the feeling after several enquiries that the flywheel wasn't dual mass.  So I guess it's likely emanating from  the clutch plate??  The local Skoda dealer say it's 'probably' the pre dampers.  Any thoughts welcome.

 

 

[Boro8688]

For the age and miles on the vehicle it wouldnt be uncommon for the noise to be coming from the clutch, The citigo gearbox/clutches are nothing fancy, basic and cheap. I would suggest getting prices from local indy garages if possible, The job itself is straight forward and the price difference between main dealer and auto parts company are massive for the clutch kit.  Just price up a kit such as valeo or LUK.

[freemansteve]

I'm still not following why a clutch issue is only when in second gear (if it is as written in the OP), but happy to have it explained.... 

[Geffix]

Thank you all for your comments to date...  The noise experienced seems to have escalated.  Now sounds like a 'knocking' noise when idling, especially when cold.  It's a rotary sound if you know what I mean.  I've been in touch wit an INDY garage who are asking their parts suppliers for the actual spec. of the flywheel, which I think may NOT be a dual mass type.  Time will tell.

 

Anyway, thanks for all your input and interest... It's appreciated.

 

Will post the outcome... good or bad!!  

 

 

[freemansteve]

OK, so no longer just a "when in second gear" thing!

 

Have you ruled out the various rubber engine and gearbox mounts being worn? These are crucial on three-pot engines because they wobble quite a lot!

 

Edited 25 June, 2021 by freemansteve

[Geffix]

Hmmmmmm... It's a thought.  Would be cheaper for sure.  Thanks.

[freemansteve]

A longshot though!  I think we are all hoping it's not the  clutch, or even worse, the gearbox

 

[KenONeill]

11 hours ago, freemansteve said:

A longshot though!

Somewhat cheaper to diagnose and, if needed, replace an engine mount, than a clutch, never mind a gearbox...

[Snaefell]

To diagnose 'neutral gear rollover', on a hill apply the park brake and let the engine idle with the clutch engaged i.e. no foot on pedal.  It should show the knocking symptoms described. 

 

Release the park brake and, in neutral, let the vehicle roll down the hill. 

 

At about 5-10mph the knocking should cease as the gears are loaded via the rotating driveshafts.

 

This is quite common for this transmission and isn't clutch related.  My 2016 Colours model started knocking at about 5k miles and currently still does it at 70k miles.  The transmission works perfectly, albeit noisily.

 

Other contributing factors include:-

1) A lack of dual mass flywheel coupled to a 'less than smooth' 3 cylinder engine. 

2) Thin transmission oil to reduce transmission drag, thereby improving fuel efficiency but not damping transmission noise.

3) A 'class leading' low mass transmission housing not damping transmission noise.

 

Below an explanation from Volkswagen from 2012:-

 

This is a documented issue acknowledged by VW and is the result of the car NOT having a dual Mass Flywheel, the device that has been causing some serious trouble on older cars. It is covered under the VW technical product information notice below that basically tells you there is nothing to worry about and nothing that can be done to stop it.

Rattling noise from engine bay at idle vehicles fitted with 02S 5 speed manual gearbox (UK TPI) Release date: 05-Dec-2012 Technical product information Transaction No.: 2032109/1

Customer statement / workshop findings

Rattling noise from the engine bay area with the engine running at idle.

Technical background

Neutral gear rollover noise describes the condition whereby a rattling noise from the constant mesh gearing in the transmission is heard while the engine idles with the clutch engaged (pedal released). 

It is caused by engine torsional vibration and is particularly prevalent on vehicles with a single mass flywheel and low idle speed requirements. The intensity of neutral gear rollover noise will increase with transmission temperature and / or an increase of torque loading, for example air conditioning or heated rear window activation. 

The rollover noise is inherent to transmission design and will disappear when a gear is selected and the vehicle is driven. The noise is not detrimental to the transmission or engine components and does not constitute a manufacturing defect. 

Production change

None.

Measure

When evaluating transmission complaints please draw on the statements above when assessing the complaint, remembering to account for engine refinement, gear selection “feel”, and clutch operation.

Warranty accounting instructions

Normal warranty guidelines apply.

Parts information

No parts information.

Customer information

Neutral gear rollover noise will not negatively affect the longevity or performance of the vehicle. It is concept related and does not constitute a manufacturing defect.

 

 

[Geffix]

Knocking noise solved... It was the clutch plate that was at fault.  The inner spline had significant movement, hence the knocking.  The new replacement had no movement whatsoever. Also the oil was like water!!

 

So, new clutch, new oil and its like new... Happy £500.00 down but still .

 

Thanks to all those who have helped, advised etc. Appreciated.

 

Geffix