Help me find this intermittent noise please!

[Gaz]

Hi guys,

My Multivan makes a very intermittent noise, it sounds like a harsh electrical buzz a lot like a relay "chattering" but only for a second or less, and it only happens maybe once every couple of days.

The only thing that is predictable about it is that it happens when the gear changes up from 3rd to 4th. It has done it in D or in S (I haven't managed to get it to happen in manual select), it can happen accelerating or coasting, it doesn't seem to matter if the engine is hot or cold, or how many times the gear have been changed in a trip.

My assumption is that it's gearbox related, but the dealers have looked for fault codes with no luck.

Any ideas?

TIA

[Sunny43.5]

What year is the van this is only a guess but would you describe the sound as more of a vibration than a noise , can you feel it through the van when accelerating . Our auto had the same sort of symptom but it was 4th to 5 th I think the description is called "flaring" a sort of slipping effect .

[BrianJ]

My radiator overflow tank mounting bracket had a massive buzz attack when it was tapped or bashed with the hand, I concluded that it would be buzzing all the time when I was driving, so packed the base between the bracket and bottle with some rubber and positioned the whole bracket so the plastic pin of the bottle could not hit the bracket.

Try wacking yours and see if it makes a noise.

[IN2VWS]

Hi guys,

My Multivan makes a very intermittent noise, it sounds like a harsh electrical buzz a lot like a relay "chattering" but only for a second or less, and it only happens maybe once every couple of days.

The only thing that is predictable about it is that it happens when the gear changes up from 3rd to 4th. It has done it in D or in S (I haven't managed to get it to happen in manual select), it can happen accelerating or coasting, it doesn't seem to matter if the engine is hot or cold, or how many times the gear have been changed in a trip.

My assumption is that it's gearbox related, but the dealers have looked for fault codes with no luck.

Any ideas?

TIA

I think I know the noise you are describing. Mine has made this noise twice.
On both occasions, the buzz lasted for ½-1 second. When it does happen, you think "What the f@#* was that?".
I can't tell you what gear I was in when it happened etc. Hasn't happened often enough...and hasn't happened for 10,000km.

[Sunny43.5]

If it is the flaring it will not show up on the dealers fault code as its not electrical its slipping of the internals a shudder if you like . Here is what I found the auto is "Sealed for Life " so VW would not open them . Inside the auto the fluid gets very hot and the molecular structure starts to decay this leads to parts wearing and the resultant particles will get into moving parts causing problems .The valve bodies component seems to be the first problem but there is more . If the fluid gets too badly contaminated it will lead to blocking the internal filter , again VW will not change them if this blocks its all over red rover . Now if I had known that unlike VW there were places who will open the sump clean and replace the filter I would not be out of pocket to the extent it did end up costing . Now this only relates to the Tiptronic NOT the DSG .

[Gaz]

I think I know the noise you are describing. Mine has made this noise twice.
On both occasions, the buzz lasted for ½-1 second. When it does happen, you think "What the f@#* was that?".
I can't tell you what gear I was in when it happened etc. Hasn't happened often enough...and hasn't happened for 10,000km.

This sounds like it. It's really quick, it's nearly impossible to tell where it comes from, but it's quite loud.

[buzuki]

The solenoids in the engine bay are mounted to a bracket on the firewall, they can often make this noise

[Gaz]

Okay, I think a solenoid might be making this noise...can anyone recommend a fix? Can I pull them out and clean the contacts?

What the heck happens between 3rd and 4th gear that fires a solenoid?

EDIT
I just found this re DSG issues:
Solenoid N89 Failure

In certain cases, an important solenoid, N89, has failed. This causes a sudden shift from gear 4 to gear 1, when the gear gets stuck at the shift from gear 3 to gear 4. This causes a sudden deceleration, similar to when the brakes are suddenly engaged.

I think I have my answer...

[Sunny43.5]

What year is the van ? DSG equipped or earlier with Tiptonic auto . The N89 seems to relate to the Tiptronic auto I just found this might help .
N89 Solenoid
In a few known instances, an important solenoid designated "N89" has failed in the Tiptronic. The Tiptronic uses a number of solenoids in different combinations to engage the gears. First and Fourth gear share practically the same solenoid arrangement, except for the # N89. If this solenoid sticks in the 3 to 4 gear change, it is possible to wind up in first gear instead of fourth. This will cause rapid deceleration, like slamming on the brakes, but so far has yet to actually damage a transmission.



Read more: http://www.ehow.com/about_5594602_vw...#ixzz2xEgBzNPL
Again I would ask does it seem like a buzzing or maybe a shudder which you can feel on acceleration .

[Gaz]

What year is the van ? DSG equipped or earlier with Tiptonic auto . The N89 seems to relate to the Tiptronic auto I just found this might help .
N89 Solenoid
In a few known instances, an important solenoid designated "N89" has failed in the Tiptronic. The Tiptronic uses a number of solenoids in different combinations to engage the gears. First and Fourth gear share practically the same solenoid arrangement, except for the # N89. If this solenoid sticks in the 3 to 4 gear change, it is possible to wind up in first gear instead of fourth. This will cause rapid deceleration, like slamming on the brakes, but so far has yet to actually damage a transmission.



Read more: VW Tiptronic Transmission Problems | eHow
Again I would ask does it seem like a buzzing or maybe a shudder which you can feel on acceleration .

My van is 2010, with a 7 speed DSG gear box.

The noise is a very harsh buzzing that lasts for less than a second, and it has only ever happened during the change from 3rd to 4th.

[Sunny43.5]

Okay that helps I have the Tiptronic T5 and a DSG T5 no noises with our DSG so all my earlier info is irrelevant Good luck though .

[greymad]

Dunno if my noise is the same - I describe it as a burping/farting/buzzing sound which seems to come from somewhere inside the engine compartment.
Maddeningly intermittent, and not able to be produced "at will", though often seems to be on lifting the foot from the throttle.
Sometimes it'll happen after switching off the motor. Great (not...). I don't believe it's linked in any way to the gearbox.

[greymad]

Dunno if my noise is the same - I describe it as a burping/farting/buzzing sound which seems to come from somewhere inside the engine compartment.
Maddeningly intermittent, and not able to be produced "at will", though often seems to be on lifting the foot from the throttle.
Sometimes it'll happen after switching off the motor. Great (not...). I don't believe it's linked in any way to the gearbox.

This is a "bounce to bring it back to the top of the queue. This thread (moderators please take note) could be combined into the other dealing with the dreaded buzz/burp/fart, which on my T5 has steadily got worse as well as more frequent.
Replacing (one of) the N75 valves has had no effect (but at least we got to find out that a twin turbo has two N75's!)
My next experiment may be to change out the vacuum hoses I read of in the other thread. This is a real pi$$er, I can tell you!