Rattling / clattering / pinging when accelerating

[SofaKing]

i’m a bit worried. 2016 150hk diesel with DSG. 28.000km on the clock. Engine starts and runs good, but when accelerating i can hear this ‘clattering’ noise. Its not very loud and initially i believed it was something loose and rattling, but found out it only appears when accelerating with engine load. Does not happen at stand still in Neutral when reving the engine.

Did not notice this in my other t6.

Anyone experienced the same/ or can hear the same?

 

[mmi]

I'm afraid you referring to a noise I tried to describe in another thread. See my last post in Anyone else got this funny noise?
I could describe the noise I had exactly with your words.

Having now new timing belt and tensioner it's a lot better - the noise is 97% gone. The noise is very rare now, even the regens are hard to distinguish. What bothers me is that the root cause has not been identified as they just ripped the old belt off not checking if that was originally installed correctly (valve timing). I leave the door still 3% ajar because I still have concerns if as consequence something has been damaged.

VW has a service bulletin about timing belt and tensioner, so they can verify with VIN if your engine is one which has failing parts. Unfortunately yours/mine "symptoms" do not match what they are looking for.

 

[SofaKing]

Thanks, I will check with VW. I’ve not seen any fault codes in Carista (except 9480753 heater and air con).

I guess VW will not do much...

 

[mmi]

Yes, this is a tough one. This one won't give any fault codes. Though there is monitoring of timings between camshaft and crankshaft but I don't know what the tolerances are so hard to tell if the fault would ever surface.

 

[mmi]

I'm afraid you referring to a noise I tried to describe in another thread. See my last post in Anyone else got this funny noise?
I could describe the noise I had exactly with your words.

Having now new timing belt and tensioner it's a lot better - the noise is 97% gone. The noise is very rare now, even the regens are hard to distinguish. What bothers me is that the root cause has not been identified as they just ripped the old belt off not checking if that was originally installed correctly (valve timing). I leave the door still 3% ajar because I still have concerns if as consequence something has been damaged.

VW has a service bulletin about timing belt and tensioner, so they can verify with VIN if your engine is one which has failing parts. Unfortunately yours/mine "symptoms" do not match what they are looking for.

Just updating my own post.

A few weeks before abovementioned unexpected replacement of timing belt and tensioner the local VW garage hooked a couple of microphones around engine and powertrain because I had been complaining about similar strange rattling and pinging noise as OP. The van was also 110kw/150PS DSG 4Motion. The noise was there only on light load, engine hot, engine revs 1400..1800 rpm, gears DSG 5-7. Went away at full throttle or zero throttle. And was especially annoying during regen.

The timing belt replacement was unexpected because the van was in for the very last warranty work – repair of oil leak from crankshaft seal. When doing that they noticed that the belt and tensioner were mentioned in service bulletin so replaced those too.​

One of the microphones was on flywheel “casing” as the prime suspect was the DMF (dual-mass flywheel). The van had about 30000 km’s then but the noise had been there since about 10000km, quiet in the beginning but getting gradually somewhat worse, or maybe I was just getting more sensitive on that. The other three microphones were on cylinder head, on the opposite end of cylinder block and at the end of gearbox.

Anyways, on the test drive the source of rattle and pinging noise was clearly pinpointed down to DMF. During the test drive also a regen took place and that was definitely nailing down the source of the noise.

Unfortunately the garage didn’t get permission to replace the DMF. So I wrote my own report about investigations and results for VW files which I could use later to still get DMF replaced under expired warranty (being a private owner).

Mysteriously the replacement of timing belt and tensioner made huge difference. The engine was sounding smooth, no rattle or pinging, very difficult even to distinguish regens anymore. So, the root cause of rattle is still unknown...

 

[Jimmy-s3]

Hey, did you ever get down to the source of the problem on this?

 

[mmi]

Hey, did you ever get down to the source of the problem on this?

Me? No definite answer as the van was not torn down. Instead the dealer put me out of the misery by making me an offer of a new van I couldn't turn down. However, the offer was based on to rectify another misery --> 4motion Abnormality And Subsequent Failure
Anyways, the subject van being driven more than a year by new owner - no repairs under warranty have been carried out.