Help with unknown noise 2009 DB9
Discussion
Hi all, I have had my DB9 for nearly 6 years, and suddenly out of the blue last month I started to hear an unidentified noise coming from underneath the car.
Sound is like a sharp ‘crack’ sound. It typically occurs at the beginning or the end of a drive, and seems to come from the drivers side (RHD car) between the front of the drivers seat and the front of the rear wheel.
It does not appear to be related to load .. speed humps, spirited driving, hard cornering do not make it occur. I’d also swear I heard it once when the engine had just been turned off.
It only started happening after I replaced all four brake pads .. but I went back and pulled all the wheels off and double checked my work and could not see any issue .. and the noise does not come from a corner of the car
The fact that it happens on warm up or cool down may suggest some kind of metal expansion/contraction and I guess it could be something like that, cars make all sorts of noises particularly when they are cooling down, but it is louder .. the timbre is not quite right for it to be just that.
Does anyone have any ideas? I have looked under the car and can’t see anything obvious
Sound is like a sharp ‘crack’ sound. It typically occurs at the beginning or the end of a drive, and seems to come from the drivers side (RHD car) between the front of the drivers seat and the front of the rear wheel.
It does not appear to be related to load .. speed humps, spirited driving, hard cornering do not make it occur. I’d also swear I heard it once when the engine had just been turned off.
It only started happening after I replaced all four brake pads .. but I went back and pulled all the wheels off and double checked my work and could not see any issue .. and the noise does not come from a corner of the car
The fact that it happens on warm up or cool down may suggest some kind of metal expansion/contraction and I guess it could be something like that, cars make all sorts of noises particularly when they are cooling down, but it is louder .. the timbre is not quite right for it to be just that.
Does anyone have any ideas? I have looked under the car and can’t see anything obvious
Thanks for that suggestion @Hutch525 I had a look today and can’t see anything unusual with the bushes. Noise does not seem to be coming from a corner of the car, but I guess noise can be transmitted fairly easily. The other perplexing thing is that I don’t hear it when I load up the car, either torsionally by going over speed bumps at an angle, or heavy cornering.
Re: noise from rear suspension.
There are rubber bushes at the inboard end of the rear control arm. These bushes are pressed into the control arm. The bush itself consists of a steel outer sleeve and a smaller inner sleeve with the rubber between. The outer metal part is a press fit in the cast aluminium control arm. The inner sleeve has a bolt through it that attaches the control arm to the chassis. Sometimes, instead of the rubber distorting to allow the control arm to move, the outer sleeve rotates inside the arm. This makes a creaking, cracking or groaning sound. Sometimes only when starting or stopping.
Diagnosis is to remove the shock and spring assembly and move the control arm up and down and listen and look to see if the bushes are moving (which is not supposed to happen). The noise is from the steel bushing rotating in the aluminium arm.
Cure is either a new control arm assembly or to press out the bushing and reinstall with Loctite retaining compound such as 680 (note not threadlocker).
It took several attempts for this problem to be traced on my Vantage.
There are rubber bushes at the inboard end of the rear control arm. These bushes are pressed into the control arm. The bush itself consists of a steel outer sleeve and a smaller inner sleeve with the rubber between. The outer metal part is a press fit in the cast aluminium control arm. The inner sleeve has a bolt through it that attaches the control arm to the chassis. Sometimes, instead of the rubber distorting to allow the control arm to move, the outer sleeve rotates inside the arm. This makes a creaking, cracking or groaning sound. Sometimes only when starting or stopping.
Diagnosis is to remove the shock and spring assembly and move the control arm up and down and listen and look to see if the bushes are moving (which is not supposed to happen). The noise is from the steel bushing rotating in the aluminium arm.
Cure is either a new control arm assembly or to press out the bushing and reinstall with Loctite retaining compound such as 680 (note not threadlocker).
It took several attempts for this problem to be traced on my Vantage.
westhumbler said:
Maybe you could record it on a video, put that on youtube and post a link on here - might give people a better idea of the noise?
I tried, but it doesn't record well .. 4x4sche said:
Re: noise from rear suspension.
There are rubber bushes at the inboard end of the rear control arm. These bushes are pressed into the control arm. The bush itself consists of a steel outer sleeve and a smaller inner sleeve with the rubber between. The outer metal part is a press fit in the cast aluminium control arm. The inner sleeve has a bolt through it that attaches the control arm to the chassis. Sometimes, instead of the rubber distorting to allow the control arm to move, the outer sleeve rotates inside the arm. This makes a creaking, cracking or groaning sound. Sometimes only when starting or stopping.
Diagnosis is to remove the shock and spring assembly and move the control arm up and down and listen and look to see if the bushes are moving (which is not supposed to happen). The noise is from the steel bushing rotating in the aluminium arm.
Cure is either a new control arm assembly or to press out the bushing and reinstall with Loctite retaining compound such as 680 (note not threadlocker).
It took several attempts for this problem to be traced on my Vantage.
thanks @4x4sche I had kind of ruled this out because I could not make the noise happen while under load, but given your comment above "..sometimes only when starting or stopping .." I will rule it back in.. It doesn't seem like a fatal noise, so will most likely now put it on the list for the dealer at next service.There are rubber bushes at the inboard end of the rear control arm. These bushes are pressed into the control arm. The bush itself consists of a steel outer sleeve and a smaller inner sleeve with the rubber between. The outer metal part is a press fit in the cast aluminium control arm. The inner sleeve has a bolt through it that attaches the control arm to the chassis. Sometimes, instead of the rubber distorting to allow the control arm to move, the outer sleeve rotates inside the arm. This makes a creaking, cracking or groaning sound. Sometimes only when starting or stopping.
Diagnosis is to remove the shock and spring assembly and move the control arm up and down and listen and look to see if the bushes are moving (which is not supposed to happen). The noise is from the steel bushing rotating in the aluminium arm.
Cure is either a new control arm assembly or to press out the bushing and reinstall with Loctite retaining compound such as 680 (note not threadlocker).
It took several attempts for this problem to be traced on my Vantage.
Gassing Station | Aston Martin | Top of Page | What's New | My Stuff