Weird Clunk - Any ideas?

[pomme]

I'm not even sure how long this has been going on... longer than the last two days in which I've really noticed it. I'm just hoping someone has some ideas, or come across something similar before.

This clunk sounds like its coming from the engine bay, you can feel a jolt through the car to accompany the clunk, and the steering wheel also moves slightly to the right, just half a then

It will occur, I believe, at all speeds, however it MUCH louder and easier to hear at low speeds (30km or under, in the video I’m rolling down a hill @ 10kms). It will occur on the first application of the brakes. If I’m off and on the brakes, each time I brake it will make the clunk... if I brake, release slightly, then reapply without fully coming off the brakes, it will not clunk any subsequent times (did this towards the end of the first video)
This has me believing that it was something to do with the brakes, however here is where it gets a little bit interesting to diagnose.... the same thing will happen if I accelerate, more so if its violent. So rolling in 1st gear, give it half throttle, the car will bunny hop, but on the settling down of the car, it will make the same clunk, though not as apparent as if I’m hitting the brakes. I could also get it to make the clunk rolling around 30 in 2nd gear and giving it a little gas and back off, the car hardly even moved at all, but still clunk and steering wheel moved etc.

To add to this... it doesn't seem to make any sound whatsoever in reverse, bunny hopping or braking. Also, I think, however can't be certain, it makes the noise going over speed bumps, down driveways on to road etc. I can't be sure as the sounds of the suspension compressing makes it difficult to tell. The only reason I even started noticing it was because my mate said it was very harsh over the speed bumps the other day.

I hadn’t noticed before because when I start braking I’m normally doing 60 and won't notice it, then brake to a stop or come off the pedal and get back on the gas, which doesn’t really make it. Therefore it may have been occurring for a while but I’m not sure.

So I’m very confused...

I had a mate walk next to the car and have a look in the engine bay while I tapped the brakes, he didn't notice anything major moving around either.

Here are a couple of videos I took on the phone, it was late, but the main thing is the sound... you can hear that it’s pretty loud on the braking one, louder than the pedal sound from the brakes, and if you brake harder it gets louder. On the accelerating one you can't really hear too well, but I chucked it up anyway.

I think I’ll get jmac to take a look soon with a nice service, but thought it would be nice to see if anyone has any ideas... or even if I shouldn’t be driving it at the moment.

http://www.youtube.com/watch?v=SxH891EZnU4 - brakes
http://www.youtube.com/watch?v=cWun3qjjRO4 - accelerating

I'll probably jump out with a dictaphone and get some clearer sound when I have time, the video is pretty useless to see anything anyway.

Edit: Polo GTI 2006 (1 month out of warranty), 80,000 k's

[break]

It's a twofold problem.

You need to replace the rear engine mount (dog bone) insert, and you need to replace the rear control arm bushes.

[pomme]

Thanks Break

I had a quick look under the car just then, and what I assume to be the rear control arm bushes are fuked.

The left one is cracked at the top... and off center (if its supposed to be in the center)... and right one doesn't seem to exsist anymore... its just gaping hole.

Dog bone, i'm assuming is the covered thing in the middle, no idea.

Would I be doing anymore damage to the car driving it round?


http://img196.imageshack.us/img196/5458/imgp0612b.jpg - left
http://img340.imageshack.us/img340/7813/imgp0611.jpg - right

[break]

<snip>

Yep, the pics you have there are of the control arm bushes (well, bush... seeing one has been completely destroyed).

Jmac is sorting me out with a set as we speak, so might be worth throwing him a PM. He's doing the upgraded bushes from the Cupra R (from memory).

As for the dog bone mount, its the engine/gearbox mount at the rear of the engine. You can get the APR insert installed for ~$150 at APR dealers.

[noone]

also Whiteline make the control arm bushes.

[pomme]

So is it a general wear and tear thing or an issue with the car. As I found a couple more on the forum now i know what to look for.

Also is driving the car like it is likely to make things worse, the other bush will obviously end up te same way, but is anything else likely to fail as a result? I'll get it sorted as soon as I can, but should garage
the car till then?

[Dans GTI]

Yea ive got some clumking noise happening with mine, alto its not as bad.

On cold starts, when i take off and the engine reaches 1500 revs, i get a clumk from the front end somewhere and i can feel it in the car. Once it has clunked, its touch wood for the rest of the drive

Anyone know what her prob could be??

[break]

Yea ive got some clumking noise happening with mine, alto its not as bad.

On cold starts, when i take off and the engine reaches 1500 revs, i get a clumk from the front end somewhere and i can feel it in the car. Once it has clunked, its touch wood for the rest of the drive

Anyone know what her prob could be??

I get exactly the same and I've had the APR dog bone insert done. I'll report back of the control arm bushes fixes that particular issue after I get my bushes done next Thursday.

[seangti]

So is it a general wear and tear thing or an issue with the car. As I found a couple more on the forum now i know what to look for.

Also is driving the car like it is likely to make things worse, the other bush will obviously end up te same way, but is anything else likely to fail as a result? I'll get it sorted as soon as I can, but should garage
the car till then?

from what I've been reading, it seems common to wear around that mileage. Obviously the harder your drive, then more premature the wear. I'd say it's premature, VW have used a compound that's too soft for the application - yet it's the compromise they've made for the car to have low NVH when new.

Someone may be able to confirm whether this bush is exactly the same as used on other polo varients, which could explain why it's too soft for the varying forces that the GTi's can generate (cornering, stopping and accelerating.

It's just a PITA the part is cheap but the install is expensive to replace with something better for the enthusiastic drive.

[MINTpolo]

Yea ive got some clumking noise happening with mine, alto its not as bad.

On cold starts, when i take off and the engine reaches 1500 revs, i get a clumk from the front end somewhere and i can feel it in the car. Once it has clunked, its touch wood for the rest of the drive

Anyone know what her prob could be??

This one off clunk after cold start is probably the ABS self test at about 15kph.

[Jmac]

I fitted a fe Super pro dogbone mounts, Pm Vwindahouse he has one fitted along with the uprated Cupra bushes.
Clunk certainly sounds like control arms, and you are up the kss too, im sure when you see them removed you will see the extent of the cracks,
I have a load of bushes in transit as we speak
Cheers
Jmac