Fixed: Plastic clonk/tap - BlueGT

[Insy79]

Hi all. So I recently purchased a 2014 BlueGT (150hp) and have to say I love it apart from a seriously annoying (don't recall it being there on test drive) clonk/tap sound that comes from somewhere behind.

I've changed out the rear suspension struts and mountings to rule that out and it's still there. I've tried driving with the parcel and false floor out the boot. Also had the seats down.

I've taken the spare wheel out along with all the random coins, etc that made it into the space and padded it all with a blanket.

But despite all this it still makes a noise mainly when turning but can occur even on just a straight acceleration.

It's almost as if a interior trim is knocking. When driving it sounds like it's on the b pillar but when you sit past it, it still sounds like it's behind. I've sat in the back and had the wife drive it around and I still can't pin point it.

Windows down and both drivers and rear door open makes no difference (was wondering if it was door not sitting right).

It's not metallic or like a thud, more of a tap of like plastic on metal sort of sound. It's so annoying as it's ruining the experience of owning it. For now I've resorted to boy racering it and having the music up to ignore the sound!

The mind boggles as apart from ripping out the entire interior, I'm not sure where to look next.

Any thoughts or suggestions gratefully received!

[veteran]

I vaguely recall a spate of complaints in these forums several months ago about tapping noises on these Polos coming from somewhere near the back of the vehicle, and as far as I can remember that turned out to be caused by one of the fuel delivery pumps (I understand there may be two such pumps on the car). Have you investigated that yet? Might be worth doing.

Another possibility, albeit a remote one, is that it might actually be coming from a brake caliper at one of the wheels. A variety of different brands of caliper have been used on the 6R and 6C Polos, with commensurate pads. Some of these combos have incorporated anti-noise shims, some don't. So that's another possibility for you.

Do bear in mind that when a source of a noise is low down, underneath the vehicle somewhere, the noise can bounce around when the car's moving and consequently appear to come from somewhere else.

I've for some time been pursuing a specifically metallic 'clank' noise of my own, associated with the clutch and/or brakes on my 1.2 TSI, and was convinced for a long time that it was sourced in the clutch itself, but I'm now not so sure; I think it might instead be coming from one of the brakes. This is something I'll be investigating quite soon. In the meantime, I hope you finally pin down yours.

[RUM4MO]

Any mileage in applying the usual lubricant to the cars and hatch seals, Krytox etc.

[iichel]

Are the bolts for the rear shocks tightened well? Been there, done that...

[Insy79]

I've just had someone else sitting in the back whilst I drove it. He couldn't pin point either. Said it almost sounded like it was something rolling around slowly.

Pretty much does it mainly on corners now.

Also have tried driving with boot lid wide open. Still there!

Not sure it's lubricant thing on the seals as it still does it with the doors/boot open.

Thanks for the tip on the caliper, next time I'm testing it I'll see if it's linked with braking.

[Insy79]

Are the bolts for the rear shocks tightened well? Been there, done that...

Yup, nice and tight.

[veteran]

Your description of the noise and when it happens fits to some extent with that found when a CV joint is on its way out, ie. general chattering sound and a 'knock-on-lock'. That's to say, a 'clonk' whenever you turn corners. But unless your car started life with a substandard CV joint and you've hammered the car since you've had it, I wouldn't expect the joint, either the lefthand or righthand one, to have worn out in such a short time. It may nevertheless be worthwhile just giving the big rubber gaiter at the back of each wheelhub (at the end of the driveshaft) a quick inspection to check that it hasn't split and is letting in muck and water, destroying that joint. Raising each front wheel off the ground and rocking it around with your hands to check for undue looseness in the hub could be done at the same time. Also worth checking would be the inboard rubberised bushes of the wishbones (lower suspension arms), particularly the rear bushes, as on these 6R/6C Polos they're apparently prone to ripping and falling apart after just a few years. Particularly with the wheel removed, you can easily look in at the inboard end of the wishbone and see the rear bush. Given that all attempts to nail down the source of the noise so far have been fruitless, these are the sorts of checks you'll need to move on to doing.

[Insy79]

The car is now going into my local dealership for them to investigate along with a noisey dash fan that flaps loudly when the air is turned off.

I'll let you all know how the dealership gets on!

[Insy79]

Ok, so we have a result!

It's fixed!

The car must have had some work done on the b pillar by the previous owner. Long story short, one of the bolts around the seat belt area had been incorrectly torqued and was putting too much tension on the bodywork so as the chassis flexed around corners and bumps, the various layers creaked together.

Bolt been replaced and fitted correctly with desired result!

On a different note the air con fan in the dashboard is confirmed to be broken (no idea how) so the dealership is waiting on the go ahead for a warranty repair from VW.

The drive home was lovely. No irksome creaking noises!

Thanks to everyone for your input.

[Globalste]

Was it a creaking noise or a tapping noise? I’m curious because I’ve had something similar on my Fabia for years and you’re the only person to come close to describing the problem the same as mine. Only occurs on warmer drier days and is usually gone the next day until the car is driven for a bit. Sounds a bit like it’s coming from the b-pillar but if you sit behind the drivers seat it seems to echo all the way through the chassis towards the rear wheel arch.

I’ve changed the struts, tips mounts etc and the noise still comes back. It’s seems to be worst on undulating surfaces, like a rough track and the car is rocking. However, if the car is stationary and I rock it I can’t replicate the noise. Speed bumps don’t make any noise.

The car has bilstein b12 suspension so the dealership are obviously blaming that, despite me changing to the bilstein to get rid of the noise.