Noise at 1350rpm

Hi guys i need help.

wierd noise coming from my 2016 T6 140HK TDI DSG, non adblue version I think it’s the last t5 engine.

The sound appears time to time, mostly when I drive and the engine is warm, but maybe 1/50 rides the sound also appears in neutral (also warm, never cold) today it did so I recorded the sound.

it’s a sparkle/crackle sound at 1300-1400 rpm, if I hold the gas steady at 1350rpm the sound reappears every second or so.


if I kill the engine restart it the sound is usually gone.

When I was done recording today I randomly squeezed the big vacuum tube? when the engine was still on, I saw it expand in one of the videos video and I just wanted to squeeze it for some reason, half a second after my squeeze the engine jumped like it was stuck before and the noise was gone and the engine sounded -as clean as it does time to time.


13800km, new flywheel last year at 12500km done by VW.
Air conditioning turned off.

2C9AB69C-603E-4A5E-A42B-5692CE0A6A8D.jpeg
 
Hi guys i need help.

wierd noise coming from my 2016 T6 140HK TDI DSG, non adblue version I think it’s the last t5 engine.

The sound appears time to time, mostly when I drive and the engine is warm, but maybe 1/50 rides the sound also appears in neutral (also warm, never cold) today it did so I recorded the sound.

it’s a sparkle/crackle sound at 1300-1400 rpm, if I hold the gas steady at 1350rpm the sound reappears every second or so.


if I kill the engine restart it the sound is usually gone.

When I was done recording today I randomly squeezed the big vacuum tube? when the engine was still on, I saw it expand in one of the videos video and I just wanted to squeeze it for some reason, half a second after my squeeze the engine jumped like it was stuck before and the noise was gone and the engine sounded -as clean as it does time to time.


13800km, new flywheel last year at 12500km done by VW.
Air conditioning turned off.

View attachment 120254
That hose you squeezed is the induction hose and is pressurised (turbo boost), you were effectively choking the air supply to the engine.
No idea what the noise is.
 
Yes, but after i choked it the engine jumped and sounded super smooth, the feeling and sound was almost as it was running on 3 cylinders and the fourth kicked in even if that’s not the case
 
Not listened properly yet...

But sounds similar to an old bmw 530d i had.... it was the inlet runner flaps on that engine...

They were vibrating in the airflow at certain rpms.

The fix on that engine was to remove the runner flap assembly from the inlet manifold (swirl flaps) and get a set of blanking plugs....if not addressed the runner flaps could break off and be ingested into the engine.

Use a stick, pole or stethoscope to listen for where the noise is coming from.

Ill look tomoz to see if that engine has runner flaps?

What engine is it exactly?
 
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Most likely CAAC - there is a configuration label under dash by steering column.

Meanwhile, check this one - although an EU6 engine.
 
this come up with a google search . .

t5 caac engine






and this . .




1624085327125.png




more info . . .




1624085452166.png

.


1624085463371.png





+++++++++++++++++++++


but cant tell from that video clip . . .


do another one similar to above . . . to see if we get a better location from where the sound was coming from.




at one point i was even thing DMF (flywheel) vibration . . .?

its just to difficult to tell.
 
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I will try make another video, Hard as I’m usually alone when the sounds appears in neutral, and i need to put my foot on the gas to rev it to 1300-1400rpm. Didn’t find anything to pull under the hood to throttle up

The sound is more from the right hand side (airbox etc) then from the opposite when im in the cockpit listening. The noise is much louder/sounds more broken in reality then in the video.

Sorry I’m from Sweden my English is not the best.
 
Odd.. same sound as you.

Wll be interesting to find out what it is.

Its low frequency... almost like a bearing rumble... but intermittent.

Possible, .....

AC clutch/bearing.?

Belt pully bearing?

Water pump bearing?

DMF rattle?


Very interesting...


Can you take it to VW and and ask then to have a listen?... maybe a diagnostic?. Just to identify the issue...

A good VW tech should know what that is straight away as it looks to be a comob symptom on that engine..... and repeatable.
 
I have the yearly inspection/service booked by the end of June, and added 1h troubleshoot for the issue. But I’m not super impressed by my local VAG center, that’s why I posted here to maybe get a clue to lead them in right direction.

I’m afraid how it’s gonna be, no sound when they searching for errors, (I understand their side off course it’s hard for them to troubleshoot without symptoms) they run it in the computer, no fail codes. 450 euros for nothing but a new pollen filter.

I get the car, next day the sound is there again.
 
I found a fellow vw owner with exactly the same noise as me, no solution yet what it seems.

At the end of the video clip:
1624098924637.png
If you just let the engine idle, do you also get disabled Stop/Start when it's happening?
 
At the end of the video clip:
View attachment 120310
If you just let the engine idle, do you also get disabled Stop/Start when it's happening?
cant talk for
At the end of the video clip:
View attachment 120310
If you just let the engine idle, do you also get disabled Stop/Start when it's happening?
Cant talk for the person in the video here, i only have the same wierd sound as him, but my start stop works when the wierd sound is accruing, and sometimes the sound disappear after the restart.
 
At the end of the video clip:

cant talk for

Cant talk for the person in the video here, i only have the same wierd sound as him, but my start stop works when the wierd sound is accruing, and sometimes the sound disappear after the restart.
Did you listen the clip I linked --> https://www.t6forum.com/threads/where’s-this-bit-from-tonight’s-quiz.8647/post-390132
Any similarity?
Have you checked air intake hoses and joints (including EGR) for leaks - basically everything from air filter to intake manifold?
 
Yes its very similar, but I think mine is worse, maybe cause I know how mine sound in real life.

I checked as good as I can, the airbox was half open since the last VAG center visit when they replaced the mass flow sensor and intercooler. No change in sound after fully closed air filter box.
My video is recorded after i closed the box.

I noticed I can force the sound to appear standing still today by holding the break and throttle when in D or R. But nothing I want to do again. But it’s good for the upcoming fail search on the VAG center.
 
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Hi. The "other" member is me and that's my video above! Its in this thread (currently right next to your thread on the engine forum...).
I'm sure its not swirl flap related as the sound is too regular. As mentioned in the other thread by @Loz it could be the air control (Moo) valve. It does only appear to happen during regens and only when warm. I've just got used to it and it doesn't seem to be getting any worse in the 15000 miles since I noticed it.
 
Not all noises are a problem, give it 15 years when we all have EV’s and we’ll want some whirrs and clicks.
 
Ok thanks for input.
maybe a harmful sound, but with 5-6k euro in repairs in a year from purchase I’d rather figure it out before another breakdown
 
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