Random Rattling / buzzing noise (video)

Jonwm

Member
T6 Pro
Morning All

Appreciate the vans all rattle (well mine does!!) but this is a bit different, over the last month my van has developed a weird rattle / buzzing noise that comes from the centre of the dash by the bulkhead, at first I thought it was something that had slipped down, it wasn't unfortunately, I've been monitoring it over the last few weeks and it seems to be only when the van is well up to temperature and under lighter load, its only between 1.7k and 2.1k revs, and it more like a buzzing.

I run the van on premium fuel and had a major service at Midland VW in November, the only thing noted was that the aux belt/ tensioner was noisy, this has squeaked at start up for over a year now so kind of dismissing its this.

Van is a factory T32 Kombi 150 DSG and has done 68k

It does good runs most weeks and the noise has become more noticeable id say as I've not been using coasting mode on the gearbox so its holding revs around that mark when off the accelerator.

Not the best videos and ones a short as I held the phone the wrong way round!

Dark one here is last night after coming home after a 30 mile drive mainly motorway, you can here the buzzing as I come round the corner to the drive and when revving in to 2k


Second video is just now after a 2 mile drive to drop kids off and its not there.


Its pointing me to think it not a loose trim panel as its really consistent at those revs and situations.

I tried to look under the engine bay but my lad hasn't got the consistency to keep it at the desired revs!! but sounds lie its coming from the bullhead area, only noticeable thing is it can sound a bit gassy too at those revs like its got an air leak or a wet fart, got told they all sound like that thought!

Its had a new EGR Flexi and filters changed.

Any help / guidance appreciated, I Am getting the tensioner aux aux belt done this month but don't think its this.

If not does anyone want to buy a van as it drives me mad haha
 
I'd be tapping all the heat shields to see if any have a tinny sound. Obviously don't try it with a red hot engine! o_O

Also check everything that is clipped to the bulkhead and make sure it's all nice and tight. You'd be amazed how much noise a fuel/brake pipe can make.
 
This might sound ridiculous, but just went to check heatshield / bulkhead and could see nothing, then I saw a flash of yellow in windscreen, got a piece of carboard down there and there is a HB pencil (not mine) down the back, I checked that weeks ago too, going out on a drive in a minute so that might be the culprit, feel a right idiot if it is that!
It also begs the question where it came from, had an MOT done on it about the same time the noise started so going to blame the ATS man if it turns out it is that!!
 
Here we go with the random suggestion...
My van developed a rattle that I was chasing round the dash for ages. I was adamant that it was behind the radio but in the end it was the rectangular panel in the ceiling trim, directly below the cubby hole in the centre.
It still comes loose occasionally and now that I know what it is, it sounds like it's exactly where it is! However, at the time the noise seemed to be from the base of the windscreen and must have been reflecting off the surfaces.
 
Wasn’t there an issue on some vans with brake pipes on the bulkhead that zing at a particular engine revs?
 
Cheers gents, I did listen at the mirror and did seem to be coming from base of the windscreen, I might do some more investigation. All I can think of that has changed is the pollen filter, not sure if that can cause a buzzing vibrating if not seated properly.

Just really weird it's only when the engine is warm.
 
Thought I'd update this thread as I may have found the problem.

It seems to have been the N75 valve, there is like a filter thing on it, its was touching the bulkhead and must be either failing or rubbed any protection off, I put some tessa tape round it to see if it helps and on todays drive its gone.

If it stays silent I'll replace the valve, I get no error codes from it but thinking it could be on its way out.
 
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