Loud knocking from rear underside of car..

[NICK87]

I have a 2016 Octavia Estate which has developed a loud " knocking" sound when going over any bumps in the road/man hole covers etc .

 

On a clear , smooth road there is no issue.

 

I have taken everything out the back of the car to make sure it's not that, I recently had it MOT and full service which had no issues at all.

 

I have had it back up on jacks and inspected and the garage said there is nothing loose or obviously causing any issues.

 

I have looked at the underside myself - part of the plastic underneath which covers all the exhaust etc seems to "rattle" and seems to have loads of grave/chippings inside it, but nothing heavy that would make the clonking/knocking sound.....

 

Any ideas ?

 

Thanks.

[Swirly182]

My guess is rear anti roll bar bushes. A decent independent garage will change them for not that much. 

[Bobbyj]

I have the same problem currently with my scoda Octavia (2016). When I drive over a slightly bumpy surface I get that rattling sound also. Scoda told me I needed new drop links but my local mechanic noticed that if you apply slight pressure to the brake when going over rough surface the noise goes away which lead him to believe that the rattle is coming from the brakes. He also told me that skoda's Volkswagen' etc don't come with anti vibration clips which causes that issue. I would suggest try applying slight pressure to the brake at a slow pace on the bumpy surface and if the noise disappears then the noise is coming from the brake. Let me know how you get on. Cheers. 

[krjh]

From my experience, it might be worth having a careful check for small stones sitting in the cups at the bottom of the rear springs.

[gregoir]

A loud knocking, from decades of previous experiences, suggests a broken exhaust mounting.

But it's probably a TLA MFD problem, which I struggled with the other day.

[BGB]

Worth mentioning is the rear shocks which has a factory fault in some 2016 models. They failed on our Octavia Scout. Naturally warranty  

[chrisski]

20 hours ago, Swirly182 said:

My guess is rear anti roll bar bushes. A decent independent garage will change them for not that much. 

had similar issue with my old skoda and it was do with these. no way would i get a main dealer to look at it. even my current octy when going over bumpy roads esp here in Edinburgh i hear slight knocking but mechanic said due to not having anti vibration clips like what Bobbyj has said.

[NICK87]

Cheers for all the replies- having just had it MOT and full service I would have thought they would have picked up on any problems regarding the exhaust or suspension but I suppose you never know !
It has been going on for a while, before I took it in .
It's still there and pretty loud - think I'll get a second opinion from another garage !

 

[Bobbyj]

A second opinion would do no harm. I found out earlier today that the brakes that were fitted by my mechanic a few months back were after market ones and scoda replaced them with the right ones. No rattle now. That's my experience anyway but as you say the rattle could be a number of things. Hope you get sorted pal. 

[gregoir]

A loud "knocking" is quite different to "rattling",  in my parlance anyway.

Verbal descriptions of underbonnet noises, booming inside cars, failing  turbochargers etc.  is getting me down. The recordings do not seem to support the owners worries.

[fat4l]

Having the same issue at the monent with my 2016 octavia vRS. They already changed "anti roll bar bushes" but didnt help. It's coming from rear(driver side) of the vehicle. Its knocking sound. Lets see what they do now. The car is going in this week(skoda dealer).

[vRSWitter]

Me too, I've got knocking when driving over bumps, seems to be coming from rear but hard to tell.

Let us know how you get on and what the cause is.

[Greenliner1]

I had a sound from my 2014 vRS that sounded like logs rolling together in the boot when going over speed bumps. All the bushes were checked OK and the fault was traced to the rear shock absorbers , a well known fault on the golf, some videos of it are available on YouTube.

 

Originally I took out the spare wheel and cover board and got the kids to listen, it was located on the passenger side rear wheel well.

 

Rear shocks replaced under warranty, no more issues.

 

Hope you get it sorted.

Edited 13 June, 2019 by Greenliner1
Removed an extra wheel!

[fat4l]

Yeha they just replaced the shock absorbers, but havent tried it yet. Will let you know when I test the car. No time atm

[fat4l]

Well yeah sound is gone. It was the rear shock absorbers replaced under warranty.

[BGB]

2 hours ago, fat4l said:

Well yeah sound is gone. It was the rear shock absorbers replaced under warranty.

 

Told you

[fat4l]

Wall mate. I just went to work and back....and the noise is back. It is a bit less noisy but still it is there lol. Whaaaattt???

 

I just made a quick video. 

Does this sound normal?

 

https://drive.google.com/file/d/1-62THF0IiblePAWJ9-vxMjRdqAvQX-Bs/view?usp=drivesdk

[benterrier]

Listened to your recording a couple of times and can hear a number of noise source's, tyre noise, other traffic, a kind of chuffing! and some notable loud clicks and taps. Would it be better if you took the recording in the cabin and not in the boot. (You sitting in the cabin can hear the problem noise). 

[CWARD]

 I’d be checking the droplinks if it’s a knocking noise over uneven ground, they tend to go before the ARB bushes. If you’re replacing them, go for quality ones like Lemforder or  Meyle HD, around £15 a corner. They’re easy to change yourself but should be no more than an hours labour at the garage. 

[fat4l]

I will do so. I will put it in the cabin....on the rear seat or somewhere there. Its just getting funny cuz the car was in the garage(skoda) for several days. First they changed antiroll ball bearing. Now Shock absorbers...Now something else will be needed ? Its unbelievable tbh.

Cward, the car is still in warranty so I will tell them to check the droplinks as you said.
Would these be changed with shock absorbers tho?

[CWARD]

No, shockers would be replaced on their own. 

[vRSWitter]

On 13/06/2019 at 10:25, vRSWitter said:

Me too, I've got knocking when driving over bumps, seems to be coming from rear but hard to tell.

Let us know how you get on and what the cause is.

 

Turns out my knocking was coming from front and it was drop links, according to garage. Yet to pick it up, but will let you know.

It was most noticeable over rough surfaces (pot holes, speed bumps etc.)

 

Yep, driver's side drop link replaced, smooth as now ...

Edited 19 June, 2019 by vRSWitter

[fat4l]

ok good I will ask for the same thing. thanks

[NICK87]

Had the car in for an oil change service and mentioned this continued loud knocking  - from the nearside front, whenever I go over any bumps in the road or the road is in anyway uneven.....

They still can't find what it is  - third garage to look at it !

It's clearly something , would it need a complete strip down somewhere to try and find it ?

[fabdavrav]

I have a possible solution......fit the "balance weight" or "harmonic damper" from the Audi A3 saloon...

 

made for the MK5 Golf, but never fitted to car until the current A3...

 

The multilink suspension/rear-subframe which was first made for the MK5 Golf/MK2 Octavia has a resonance problem...& there are no bushes between the subframe & the body...so it amplifies the noise..

 

I fitted the item to my MK7 Golf estate about 2 months ago..& its so much quieter...

 

Parts list & approx. costs in UK £
Item No.6:- 1K0 505 563, Balance weight, £58.65 (x1)
Item No.7:- N 901 838 03, Hex collar nut self-locking M8 (A03G), £0.81 (x2 quantity)

 & do the nuts up to 18Nm...(thorough lubricated setting)

 

I did a how to guide on the MK7 Golf forum, but the site is having updates so cannot link ATM