997.1 gt3 rattling / clunking sound left front when warm - Page 3 - Porsche General - PistonHeads UK

I am having clunking sounds from the front in my 997 gt3. Appears to be only when warm after a period of driving. I even hear if right after I stop sometimes. Heres a link to similar sound. Any thoughts? https://www.youtube.com/watch?v=tjaL8hDVUzQ https://www.youtube.com/watch?v=1c_v83XU548

Morning! Most likely culprit is either or both of the strut top mounts. If it's not those, second suspect would be the anti roll bar drop link(s)

From 2016 : Slippydiff said: It'll be one of the following : 1 The spherical bearings in the strut top mounts are worn . 2 The anti roll bar drop link ends (balljoints) are worn. 3 The front strut damper rod bushings are worn (frequently gets worse after a few miles driving as the dampers heat up) 4 Front coffin arm outer balljoints worn. 5 Anti roll bar bushes worn or dry. 6 Coffin arm inner bushings worn 1,2 & 3 (or combination of all three) are common issues. Most OPC's will fail to or wrongly diagnose issues 1,2&3. Bite the bullet, book the car in one of the well known and regarded specialist Indys, or if you want the car set up and fettled to a standard few others will attain, book it in with Chris Franklin at Center Gravity. HTH.

Thanks. Sometimes I can hear the sound when stopped. Does that help to sort out which problem it is?

9971gt3 said: Thanks. Sometimes I can hear the sound when stopped. Does that help to sort out which problem it is? Stationary but turning the steering wheel ? Or stationary but releasing your foot off the brakes after having applied the brakes ?

I am 99% it was after releasing the brakes. Dont think the steering affect the sound. Also hear it if braking hard or accelerate

9971gt3 said: I am 99% it was after releasing the brakes. Dont think the steering affect the sound. Also hear it if braking hard or accelerate Don't ignore the 'tuning forks' or 'forked arms' - although our 997 is a Carrera S rather than a GT3, the NSF tuning fork arm was causing a quiet, but distinct, knocking noise when puling up slowly at, say, traffic lights. The joys of multi-link suspension on a 911 with a few years/miles on it...

9971gt3 said: I am 99% it was after releasing the brakes. Dont think the steering affect the sound. Also hear it if braking hard or accelerate It could be the brake pads rattling in the calipers due to the adhesive on the "stickies" that stick the pad backplate to the caliper pistons, having failed due to overheating. But it's just as likely to be the coffin arm outer balljoints having dried out, likewise the same (balljoints) on the anti roll bar droplinks or indeed the diagonal compression struts. As I mentioned in my earlier quoted post, you really to need to find an independent who's familiar with the GT3's front suspension, in order that they diagnose it quickly and accurately, otherwise they'll end up bolting on lots of new parts that they think may be causing the issue, but all too frequently isn't ...

I’ll go with tuning forks, my 996 had similar. No noises or play when cold but definitely knocking after driving some way and the suspension joints had warmed up.

I’ll go with tuning forks, my 996 had similar. No noises or play when cold but definitely knocking after driving some way and the suspension joints had warmed up.

I’ll go with tuning forks, my 996 had similar. No noises or play when cold but definitely knocking after driving some way and the suspension joints had warmed up.

Richard-cqpvd said: I’ll go with tuning forks, my 996 had similar. No noises or play when cold but definitely knocking after driving some way and the suspension joints had warmed up. The tuning forks are also referred to as "diagonal arms" or "compression struts", hence I mentioned them in my post above

Centre Gravity diagnosed a similar noise on my 997.1 GT3 several years ago. From memory it was the "DU bushes" in the front dampers, which (I think) could be item no. 3 in Slippy's list above

Check between the anti-roll bar and the subframe for a stone or similar; have seen where they get taken into the undertray and then fall down between the bar and the frame. As the bar turns relative to the frame the stone gets ground into the adjacent parts causing a noise very similar to that in the first video - especially if it just started randomly.

Many thanks for help here. I forgot to mention that the car was just at Porsche center one week ago the same day I bought the car. And they could not find anything at that moment. It was in the days after on the transport drive home we heard this strange sound several times. Porsche center now confirm that they did a normal service and checked the suspension, brakes, control arm etc last week. They could not find anything I took it for a 30 minute drive yesterday and the knocking sound was gone. I think the sound occur only in low speed after longer driving at higher speed and/or after hard braking/ acceleration

9971gt3 said: Many thanks for help here. I forgot to mention that the car was just at Porsche center one week ago the same day I bought the car. And they could not find anything at that moment. It was in the days after on the transport drive home we heard this strange sound several times. Porsche center now confirm that they did a normal service and checked the suspension, brakes, control arm etc last week. They could not find anything I took it for a 30 minute drive yesterday and the knocking sound was gone. I think the sound occur only in low speed after longer driving at higher speed and/or after hard braking/ acceleration Hence my suggestion you should get the car checked over by one of the well regarded independents. they'll have both the time and inclination to establish where the noise is coming from and rectify it cost effectively.

rrroro said: Centre Gravity diagnosed a similar noise on my 997.1 GT3 several years ago. From memory it was the "DU bushes" in the front dampers, which (I think) could be item no. 3 in Slippy's list above This was a known fault back in the day. I had new dampers under warranty. You can only hear it when the cars is warm and on a slightly uneven surface at slow speed. Any real load in the suspension and the slack is gone and you won’t hear it.

ttdan said: This was a known fault back in the day. I had new dampers under warranty. You can only hear it when the cars is warm and on a slightly uneven surface at slow speed. Any real load in the suspension and the slack is gone and you won’t hear it. This ^ Some years ago Bilstein developed modified DU bushes (different material and a design that increased the surface area) to address the issue. However, the noise the OP demonstrated in his videos didn’t sound like damper rod bushes to me.

Agreed, it will be worn bushes in the Bilstien shocks. Had this issue with mine. Sent all four shocks back the Bilstien UK for a full referb, no problems since. Edited by Retept on Tuesday 22 March 22:34

Thanks guys. I will do a test drive with chief tech at the most "experienced with gt cars" porsche center in my country. He said exactly what you said about not changing the whole front We dont have any independent workshops like the ones you have I think. The car had sat for almost 2 years with little use before I bought it. The brakes was screaming like hell and also some rattling sound while braking and I did some hard braking after a while the first day after picking up. Then the sound from the brakes went away for a period. But still screaming from time to time. The day after, when we came off the highway the new strange sound appear for the first time at low speeds.

Brake noise will be excess corrosion on the inner face of the front discs, or the handbrake shoe linings breaking up, or one of the handbrake shoe retaining springs have failed.

Ok, I think that is ok after some use now. But you also said something else about the brakepads rattling? Is that maybe the problem here?

9971gt3 said: Ok, I think that is ok after some use now. But you also said something else about the brakepads rattling? Is that maybe the problem here? I think it's very unlikely, I'd be inclined to look at the anti roll bar bushes, anti roll bar drop link ends, or the coffin arm balljoints, or the coffin arm inner bushes.

Thanks.Yesterday I went for a 2 hour drive to try get the sound and record it. But it was almost no rattling at all, only one sec at the end of the trip while going in to the garage. It was 2 hours with both highway and B-roads 80-120kmh. The climate is colder here where I am now(norway) The annoying rattling sounds first came after driving hours on highways in Germany with higher avarage speed. It was there constantly at low speeds after going off the highway. The temperature were 10 degrees higher at that time. Should I just wait to see if it get worse?

9971gt3 said: Thanks.Yesterday I went for a 2 hour drive to try get the sound and record it. But it was almost no rattling at all, only one sec at the end of the trip while going in to the garage. It was 2 hours with both highway and B-roads 80-120kmh. The climate is colder here where I am now(norway) The annoying rattling sounds first came after driving hours on highways in Germany with higher avarage speed. It was there constantly at low speeds after going off the highway. The temperature were 10 degrees higher at that time. Should I just wait to see if it get worse? If you enable your PH account to accept emails, I'll send you some suggestions as to how to eliminate some of the bushes and balljoints from the equation, establishing which components are causing the noise should then be more straightforward.

I think I have enabled it now

Hi Magnus, Email received, I’ll respond in the next 24 hours

9971gt3 said: Thanks.Yesterday I went for a 2 hour drive to try get the sound and record it. But it was almost no rattling at all, only one sec at the end of the trip while going in to the garage. It was 2 hours with both highway and B-roads 80-120kmh. The climate is colder here where I am now(norway) The annoying rattling sounds first came after driving hours on highways in Germany with higher avarage speed. It was there constantly at low speeds after going off the highway. The temperature were 10 degrees higher at that time. Should I just wait to see if it get worse? These are the exact symptoms I had for almost 2 years. Only after long drives the knocking would start when diving slowly.

Yesterday I had a longer trip and the sound came back after a few hours. No need to turn or brake. Its constantly there after some time. In speeds up to 50kmh then I think engine/road noise are too loud to hear. https://vimeo.com/manage/videos/692582558 https://vimeo.com/manage/videos/692578849

Hi, I’m from Taiwan, just got a 08 997.1 GT3 and found same weird sound as your video. Do you figure out the root cause and problem solved from your last post? Thanks! 9971gt3 said: Yesterday I had a longer trip and the sound came back after a few hours. No need to turn or brake. Its constantly there after some time. In speeds up to 50kmh then I think engine/road noise are too loud to hear. https://vimeo.com/manage/videos/692582558 https://vimeo.com/manage/videos/692578849

Hi I have not done anything yet. Its still there, but I dont think it affects performance?

JamesFan33 said: Did you sort this out? Are these top mounts normal or have they moved? Looking at the nuts

Heres another video. Driving slow on a pretty flat straight road. The sound turns up after 30-60 minutes drive. The sound does not get any worse on dumps or when dampers are more compressed. Have lubricated swaybar bushings and top mounts with no result. I spoke to bilstein rebuild service in UK and they can rebuild the dampers. And they said this is a common problem and maybe my problem according to what I told them. What do you think? https://vimeo.com/768275822

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Does anyone have a DIY or youtube link on how to remove/replace 997 front damper?

9971gt3 said: Does anyone have a DIY or youtube link on how to remove/replace 997 front damper? It's not a video, but this is one of many excellent how-to guides you can find on Pelican Parts. There's a step-by guide as well as helpful pics at the bottom. https://www.pelicanparts.com/techarticles/Porsche-... Hope this helps.

It's the front control arms. Only happens when warm - after driving - and worse at low speeds on rough surface, and often heading down hill. Sounds a bit like snooker balls in box. They will feel normal - ie no movement - when checked but take them off and the play becomes apparent. Not generally an issue for handling, just an annoying noise. Had this twice on my car. Edited by anonymous-user on Friday 2nd December 12:09

Discombobulate said: It's the front control arms. Only happens when warm - after driving - and worse at low speeds on rough surface, and often heading down hill. Sounds a bit like snooker balls in box. They will feel normal - ie no movement - when checked but take them off and the play becomes apparent. Not generally an issue for handling, just an annoying noise. Had this twice on my car. Edited by Discombobulate on Friday 2nd December 12:09 There are so many saying that its the DU bushes in the bilstein dampers and some also think its the droplinks. And now we have the control arms. Are all these parts making the same rattling/clunking like the videos I posted?

9971gt3 said: There are so many saying that its the DU bushes in the bilstein dampers and some also think its the droplinks. And now we have the control arms. Are all these parts making the same rattling/clunking like the videos I posted? Everyone could be right. But I have done 60k in my car and had it happen twice - sounds just like yours - and control arms was the problem. The clue is that the problem isn't there when cold which it probably would be with drop links and top mounts. The control arm does get warmer, but most importantly has metals / ball joint that expand differently (the aluminium arm more than the steel bits) allowing movement when hot. But the only way to be sure is to change the bits and see. Up to you where you start. Been there so know what it feels like Mine was diagnosed by Pete at Center (sic ) Gravity. You could always try sending him the video.. Good luck.

9971gt3 said: There are so many saying that its the DU bushes in the bilstein dampers and some also think its the droplinks. And now we have the control arms. Are all these parts making the same rattling/clunking like the videos I posted? The dampers were my problem 60k + miles....Could have had them serviced, but replaced with ohlins (bilsteins now sitting on a shelf). I've now a more adjustable, compliant suspension set up...so win, win

Discombobulate said: Everyone could be right. But I have done 60k in my car and had it happen twice - sounds just like yours - and control arms was the problem. The clue is that the problem isn't there when cold which it probably would be with drop links and top mounts. The control arm does get warmer, but most importantly has metals / ball joint that expand differently (the aluminium arm more than the steel bits) allowing movement when hot. But the only way to be sure is to change the bits and see. Up to you where you start. Been there so know what it feels like Mine was diagnosed by Pete at Center (sic ) Gravity. You could always try sending him the video.. Good luck. One day I will have problems with the dampers also if thats not the problem. They are 120 punds each to rebuild and get the springload checked and topmounts checked at the same time at bilstein rebuild service. I start from there. Replacing the drop links are cheap as well. Control arms are more expensive I think. Hopefully its not that

sounds like the shocks need refurb/replacing. How did you get on?