Vibration behind bonnet release from 1500-2500pm when cold

G'day,

I've got a 2018 162tsi Tiguan and it's now at 17,000kms. In the last 1,000kms it's developed an annoying vibration buzzing sound that's coming close to the bonnet release just near the drivers right foot.

One of the challenges in replicating and isolating the noise is that a) the noise stops, well it's not as accentuated when the door is open, v.s. closed and b) when the car warms up, such as getting to the dealer, the noise quietens down and eventually stops.

It's quite loud in the mornings and only happens when the engine moves from roughly 1500-2500 rpm in all gears. If you stop and put the car in neutral or in park and rev the engine, the same problem is there.

I've tried to get my head down into that space with the car in park and rev the engine to 2000pm and I can hear it but I can't work out where it's coming from. It's not vibrating any of the plastic surrounds, so placing my hand on different items doesn't help me work out where it's coming from.

By having my head down near the accelerator, I can almost isolate that the problem is not coming from the door or from the dashboard trim against the door, which is what my dealer said it likely is, I don't agree.

What I can see behind the bonnet release are a number of wiring looms and potentially relays. Is it probable this is where the problem is coming from (ie has anyone experienced this sort of sound before either in this scenario, or from a relay) and if not, does anyone know what is behind the bonnet release, what the controls and wiring is there? I had a look in the workshop manual and couldn't figure it out.

Open to ideas :)
Matt

If you can reliably replicate the noise with those steps, leave it at the dealership overnight and get them to have a crack on a cold start. Also take videos to at least prove it’s happening for when they say they can’t figure it out 😂

Yeah, thanks. I’ve attempted to record it. Seems that I’m attracting all sorts of noises in this car. Don’t have a problem with the Polo or the Golf we had before. Is it just me, or my car or do others have rattles and different noises arising from theirs? To be fair and reasonable I have test driven another one exactly like mine and it doesn’t have the noises I’m encountering, maybe they set in after 10,000kms ....

Mine has a few early bits throughout the plastics. None terrible. Worst thing is they’re intermittent and hard to find the cause

Good to know thanks Simon. These noises are driving me crazy...

I had a vibration in the side pillar, next to the driver's seat. Heard when the DSG decided not to down shift when going up hill, causing the car to slightly vibrate. It went away at about 5000km.

I had a rattle in a similar location when i had my Mk6 Golf R. Took me ages to track it down and i found multiple nuts and bolts along the way (in that area which is where the fuse panel was) that were loose - i got super excited each time i found something loose as i was sure this would be the fix. Took the steering wheel off, dash cluster out, wiper arms etc etc, soundproofed everywhere etc. Big job over multiple weeks/months.

In the end, it turned out to be the most basic thing and i was absolutely dumbfounded/embarrassed that i didn't find the source within 5 mins. I had a P3 gauge that was plugged into the OBD diagnostic port (down near the bonnet release) and it must have had a piece of solder/plastic inside the plug that has become dislodged and was rattling around in the plug. It only rattled at a certain RPM range so impossible to replicate in the driveway at home.

Help me locate this dash rattle in my Golf R. $100 prize for correct diagnosis

Just turn the stereo up!
But seriously, I’ve slapped a few plastic panels to get rid of a couple of similar (speed/rpm) rattles.
One was in the sunglasses box in headliner - drive me nuts. I could’ve sworn here was a screw loose in there...and started to wonder if the screw was loose in my head.... turned out a trim clip not fully engaged, a firm slap with open palm sorted it.
Another was in the A pillar. Not sure if it was a clip or I just shook a bit of loose plastic out of the way but noise is gone.
I suspect someone had the headliner out somewhere between factory and dealer delivery to me... but I don’t have a sunroof, so it wasn’t the sunroof led recall.

Just an oddball thought Someone hasnt put something in the little drivers side glovebox and its resonating at that speed have they.