Knocking noise from rear? - it'll be the tailgate...

Chat about your 2018+ AW model Polos here!
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

For anyone suffering from a knocking from the rear end of their car, I don't know what VW's problem with tailgates in these cars - but they have one. :cry:
This is my second Polo in a row with tailgate noise issues.
Anyway, here's a possible cure; :!:

1. Open the tailgate, look up and you'll see a rubber 'bump stop' either side of the tailgate itself.
2. The rubbers just spin on top of a piece of plastic, but if you pinch the rubbers you can then make the plastic underneath move - they click as they move
3. Clockwise makes them move in towards the bodywork, and vice versa.
3. Click in or out and experiment until you make the knocking stop.

I've just wound both of mine fully in and knocking has stopped - completely.
I can't see/feel/hear any issues with them being wound fully in, no ominous metal to metal knock when I close the tailgate.
I can go weeks between using the tailgate anyway.
Unless anyone can see any harm in me having them fully wound in, I intend to leave them....?
SRGTD
Bling Bling Diamond Member
Posts: 2293
Joined: Sun Oct 11, 2015 9:40 pm
Drives: 2020 AW Polo GTI+, Pure White.
Location: UK

Re: Knocking noise from rear? - it'll be the tailgate...

Post by SRGTD »

I think that’s what those bump stops are for - to stop unwanted movement and resultant noises between the tailgate and the tailgate aperture, so adjusting them shouldn’t do any harm.
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Re: Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

SRGTD wrote: Mon Oct 05, 2020 12:50 pm I think that’s what those bump stops are for - to stop unwanted movement and resultant noises between the tailgate and the tailgate aperture, so adjusting them shouldn’t do any harm.
I'm assuming they must leave the factory with a pre-set number of clicks, no actual checks are made to see if there's noise.
Hopefully this may help anyone else with a noisy rear-end (ooh matron) avoid a trip to the dealer.
TheRacingRat
New
Posts: 44
Joined: Mon Jun 01, 2020 1:47 pm
Drives: 2020 Polo GTI+
Location: Suffolk

Re: Knocking noise from rear? - it'll be the tailgate...

Post by TheRacingRat »

I wish mine was the tailgate. MD have had my car for 3 weeks now and still cannot diagnose the offside rear knock noise, Master technician can’t sort it, been in touch with VW technical to now avail, spring/shock/top mount replaced to no avail. Now they think the noise is in the body work so it’s now at their approved body shop who is trying to trace the problem. I’m getting fed up now, got the car July 9th and only done 940 miles as it was hit and repaired(1 Week in body shop) had it back for 1 week now at MD for 3 weeks. Should I just get it back if they haven’t sorted it by end of week? They have been very helpful I’ve got a nice r line golf as a loaner but I really want my car back🙄
monkeyhanger
Bling Bling Diamond Member
Posts: 2307
Joined: Fri Feb 23, 2018 9:58 pm
Drives: Audi A4 Avant Quattro 40 TDI, Polo GTI+
Location: Newcastle upon Tyne

Re: Knocking noise from rear? - it'll be the tailgate...

Post by monkeyhanger »

Surely if the bump stops are fully wound in then they're not doing their job of maintaining a certain gap between tailgate and the back of the main bodywork of the car?

When the boot aperture catch for the tailgate lock was set too far in on mine, it required a bit of a slam on the bootlid to close it - was that happening with yours Andy?

Seems a common issue, a few other people reported same thing.

If winding the boot stops fully in cures a bounce knocking, it would suggest to me that the gap between where the boot stop would have the tailgate naturally fall to and where the aperture catch would have it rest are far bigger than they should be, putting the tailgate under tension and requiring a slam to close. Having the tailgate sit a lot closer to the aperture than intended will have the lower inner edge of the tailgate rub on the top of the rear bumper, as happened to mine.

I'd suggest that your bump stops were probably correctly adjusted to where the aperture catch should be (but probably isn't.

Somewhere in an old thread I have shown correct and incorrect placement of the catch (pre-adjustment) and photos of the rubbed paint.

Might be worth you posting a birds eye view of the catch on your car - Square down form top of the catch to the plastic trim slot/hole cutout.

If the catch is correctly adjusted, virtually no effort is required to close beyond gravity from the tailgate drop from horizontal position.

Are the panel gaps between aperture and tailgate consistent from top to bottom when the side of the car is viewed?
Last edited by monkeyhanger on Thu Oct 08, 2020 5:44 pm, edited 1 time in total.
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Re: Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

The effort required to close the tailgate hasn't changed between knocky-knocky bumpstop level and quiet bumpstop level.
I may wind them off a bit so they're not fully in, but sod's law is that one of them won't budge with my fingers now and will need a pair of pliers.
I'll do it 'tomorrow'
sautor
New
Posts: 1
Joined: Sat Sep 26, 2020 4:28 pm
Drives: 2018
Location: Poland

Re: Knocking noise from rear? - it'll be the tailgate...

Post by sautor »

TheRacingRat wrote: Wed Oct 07, 2020 5:46 pm still cannot diagnose the offside rear knock noise🙄
Hi. Sorry for my English.
Is it knocking like in that movie?
https://www.youtube.com/watch?v=01ZTzJsIvDo
In my case, the reason was the headlight leveling sensor. It was loose. It is located at the rear wheel.
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Re: Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

I wound the bump stops back out a couple of turns.
Instant return of the annoying knock, so they're back to fully wound in.
I will have to get it booked in, at some point.
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Re: Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

Knocking even with the bump stops wound fully in now.
Therefore no option but to book the damned thing in, for an exact same fault as my Beats.
Jesus wept repeated faults are so damned annoying. :evil:
TheRacingRat
New
Posts: 44
Joined: Mon Jun 01, 2020 1:47 pm
Drives: 2020 Polo GTI+
Location: Suffolk

Re: Knocking noise from rear? - it'll be the tailgate...

Post by TheRacingRat »

After 3 weeks at the dealer it seemed the noise was fixed but after a few days it returned. This noise is coming from the petrol cap area, it’s almost more like a pop noise than a knock. I’ve decided just to live with it as it’s not loud and it comes and goes and I don’t want to be without the car for weeks on end again. The MD/head technician in contact with VW HQ couldn’t fix it in 2 weeks, and then their approved body shop had it for a week and couldn’t fix it, so I guess it will remain a mystery?? Loving the car apart from this.-and mines not mooing yet :mrgreen:
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Re: Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

TheRacingRat wrote: Sat Oct 31, 2020 7:18 pm After 3 weeks at the dealer it seemed the noise was fixed but after a few days it returned. This noise is coming from the petrol cap area, it’s almost more like a pop noise than a knock. I’ve decided just to live with it as it’s not loud and it comes and goes and I don’t want to be without the car for weeks on end again. The MD/head technician in contact with VW HQ couldn’t fix it in 2 weeks, and then their approved body shop had it for a week and couldn’t fix it, so I guess it will remain a mystery?? Loving the car apart from this.-and mines not mooing yet :mrgreen:
Have you tried the 'cloth experiment'?
On both my Polos it's the right hand side of the tailgate that knocks.
Just put a cloth between the body and the tailgate, you can do it so it doesn't show when the tailgate is closed - if the noise stops it's the tailgate.
I went for months like this on my beats as I rarely use the tailgate and it saved me a trip to the dealer.
I may do the same on my Gti, dealer trips really are a damned inconvenience for me.
TheRacingRat
New
Posts: 44
Joined: Mon Jun 01, 2020 1:47 pm
Drives: 2020 Polo GTI+
Location: Suffolk

Re: Knocking noise from rear? - it'll be the tailgate...

Post by TheRacingRat »

No I haven’t so I’m gonna do this this week, if it’s this I will laugh to myself, goodness knows how much VW spent over 3 weeks trying to resolve it. I did mention the cloth thing when I first booked it in.
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Re: Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

I finally remembered to put a cloth between the tailgate and body this morning, I'm so rarely in the boot I keep forgetting.
End of knocking again.
It's booked in for 23rd.
User avatar
PO10ASH
New
Posts: 26
Joined: Sat Sep 03, 2016 1:35 pm
Drives: POLO GTI+
Location: Nottingham, United Kingdom
Contact:

Re: Knocking noise from rear? - it'll be the tailgate...

Post by PO10ASH »

TheRacingRat wrote: Sat Oct 31, 2020 7:18 pm After 3 weeks at the dealer it seemed the noise was fixed but after a few days it returned. This noise is coming from the petrol cap area, it’s almost more like a pop noise than a knock. I’ve decided just to live with it as it’s not loud and it comes and goes and I don’t want to be without the car for weeks on end again. The MD/head technician in contact with VW HQ couldn’t fix it in 2 weeks, and then their approved body shop had it for a week and couldn’t fix it, so I guess it will remain a mystery?? Loving the car apart from this.-and mines not mooing yet :mrgreen:
I've got a rear knocking noise, but I would describe it more in the location as TheRacingRat. I've thought it's might've been the fuel pump, as if you put your ear on the rear drivers side seat you can hear it nice and clear. I'm around 2.5k miles in, and I'm noticing a few more things, handbrake rattle, rear mooing (obviously) and recently when turning sharply right there appears to be some kind of scraping noise. :roll:
I'll get it booked in at some point, to let them have a look, but might have to try your trick Andy as it's much easier than a trip to the dealer, like yourself I use my car so often it's just an inconvenience.
Andy Beats
Platinum Member
Posts: 1443
Joined: Tue Nov 13, 2018 1:12 pm
Drives: Polo GTI DSG with upgraded 18" wheels
Location: aberdeen

Re: Knocking noise from rear? - it'll be the tailgate...

Post by Andy Beats »

VW should do an official tailgate cloth.... :roll:
Post Reply