Fordmods Logo

Mystery Noise 

 

Page 1 of 2 [ 23 posts ] Go to page 1, 2  Next

 
 Post subject: Mystery Noise
Posted: Fri Apr 23, 2010 11:29 am 
Stock as a Rock
Offline

Age: 27

Posts: 133

Joined: 10th Aug 2008

Ride: Falcon AUII

Location: Gold Coast
QLD, Australia

Hey guys.

My car has a loud clunking noise coming from the rear of the car and so far my mechanic and exhaust shop have been useless in diagnosis.

The noise happens after the car has been driven for about 20 minutes, and is in gear (It's an auto) braking or when its a complete stop. If you put the car in neutral the noise disappears.

The exhaust shop couldn't get the car to make the noise when I had it with them, but they said that the rear muffler was rusted and should be replaced. So I got them to put a 2.5inch catback on. This however just made the noise louder so I assumed that it must not have been the exhaust and took it to my mechanic to see what he thought.

He had it for a day and couldn't get it to repeat the noise so I took it out for a spin the next day and showed him the noise myself. He said that he was sure it was the exhaust just vibrating against something caused by the vibrations of the engine and that I should take it back to the exhaust shop to get them to fix it.

I then took it home, and checked the exhaust myself and as far as i can see the exhaust has enough clearance the whole way. So now I'm back to square one.

Any ideas what could cause such a noise?

 

_________________

....what goes here?

Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 11:48 am 
Tyre Shredder
Offline
User avatar

Age: 52

Posts: 358

Joined: 7th Jun 2007

Ride: NA Fairlane / FE LTD

Location: bayswater
VIC, Australia

Check you engine mounts. They tend to wear on one side because of engine torque. good place to start coz AU's getting on know so could be time.
Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 12:31 pm 
NSW Cruise Moderator
Offline
User avatar

Age: 39

Posts: 7331

Joined: 5th Nov 2004

Gallery: 12 images

Ride: TE50

Location: ɹǝpun uʍop
NSW, Australia

Rear of car rules out engine mounts.

If its IRS I would look at the bushes there, if perished or floged out, they can walk a bit and generate noise, if live rear end, upper and lower control arms may be the culprit.

It could also be a dry bush creaking away too? Just a few different things to look at.

Does it sound like a knock on the body or chassis? of is it dampend a bit?

 

_________________

Image

I have a car.

Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 12:43 pm 
Tyre Shredder
Offline
User avatar

Age: 52

Posts: 358

Joined: 7th Jun 2007

Ride: NA Fairlane / FE LTD

Location: bayswater
VIC, Australia

dc_todd wrote:
Rear of car rules out engine mounts.

If its IRS I would look at the bushes there, if perished or floged out, they can walk a bit and generate noise, if live rear end, upper and lower control arms may be the culprit.

It could also be a dry bush creaking away too? Just a few different things to look at.

Does it sound like a knock on the body or chassis? of is it dampend a bit?

Cant be suspesion because it does it at a complete standstill.
Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 12:58 pm 
Fordmods Newbie
Offline

Age: 25

Posts: 19

Joined: 18th Apr 2010

Ride: EF Falcon

Location: Toowoomba
QLD, Australia

What about the diff? you said it goes away when you put it in neutral. Im not expert and i don't know much about the diffs but if you change gear and it stops could it be something to do with that section of the car?
Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:00 pm 
Stock as a Rock
Offline
User avatar

Age: 25

Posts: 111

Joined: 24th Sep 2005

Gallery: 1 images

Ride: NA Fairlane

Location: Melbourne
VIC, Australia

diff doesn't turn when the car is stationary.

i think you need to describe the problem a little more as it doesn't quite make sense.
are you sure you got the details correct OP?
Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:01 pm 
Tyre Shredder
Offline
User avatar

Age: 52

Posts: 358

Joined: 7th Jun 2007

Ride: NA Fairlane / FE LTD

Location: bayswater
VIC, Australia

There are no moving parts at the rear of the car at a complete stop except the fuel pump. When I put my ltd in neutral all the rattles go away, and I think its because of the faster idle. When my car warms up, about 15 to 20 mins, the S5 in the tranny plays up and the clunk causes a resonance through the chasis, but does not do it at a stop.
I think we are going to need more information to solve this one.
Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:07 pm 
NSW Cruise Moderator
Offline
User avatar

Age: 39

Posts: 7331

Joined: 5th Nov 2004

Gallery: 12 images

Ride: TE50

Location: ɹǝpun uʍop
NSW, Australia

nalane wrote:
dc_todd wrote:
Rear of car rules out engine mounts.

If its IRS I would look at the bushes there, if perished or floged out, they can walk a bit and generate noise, if live rear end, upper and lower control arms may be the culprit.

It could also be a dry bush creaking away too? Just a few different things to look at.

Does it sound like a knock on the body or chassis? of is it dampend a bit?

Cant be suspesion because it does it at a complete standstill.


It can still be IRS mounts or control arms, when the car sits idle with the engine running, if a worn bush is preloaded the engine vibration can make things move enough to creak, but clunk is a different issue.

Out of interest have you checked your drive shaft bolts?

It can still be suspension even at standstill. stuff still moves.

 

_________________

Image

I have a car.

Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:15 pm 
Getting Side Ways
Offline
User avatar

Age: 39

Posts: 843

Joined: 20th Feb 2010

Gallery: 2 images

Ride: AU Fairmont Ghia

Location: Elizibif Norf (Local Spelling!!)
SA, Australia

dc_todd wrote:
It can still be suspension even at standstill. stuff still moves.


Agreed. While your car is parked, engine off etc, try and 'bounce' the car up and down as well as side to side and listen for any strange noises. Hope this helps.

 

_________________

dc_todd wrote:
Cheap pads squeal like cheap hookers, and you can take that to the bank.


Au Fairmont Ghia
My (Old) 95 EF Wagon

Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:22 pm 
Tyre Shredder
Offline
User avatar

Age: 52

Posts: 358

Joined: 7th Jun 2007

Ride: NA Fairlane / FE LTD

Location: bayswater
VIC, Australia

dc_todd wrote:
nalane wrote:
dc_todd wrote:
Rear of car rules out engine mounts.

If its IRS I would look at the bushes there, if perished or floged out, they can walk a bit and generate noise, if live rear end, upper and lower control arms may be the culprit.

It could also be a dry bush creaking away too? Just a few different things to look at.

Does it sound like a knock on the body or chassis? of is it dampend a bit?

Cant be suspesion because it does it at a complete standstill.


It can still be IRS mounts or control arms, when the car sits idle with the engine running, if a worn bush is preloaded the engine vibration can make things move enough to creak, but clunk is a different issue.

Out of interest have you checked your drive shaft bolts?

It can still be suspension even at standstill. stuff still moves.

OP says loud clunk from rear.
Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:36 pm 
NSW Cruise Moderator
Offline
User avatar

Age: 39

Posts: 7331

Joined: 5th Nov 2004

Gallery: 12 images

Ride: TE50

Location: ɹǝpun uʍop
NSW, Australia

nalane wrote:
dc_todd wrote:
nalane wrote:
dc_todd wrote:
Rear of car rules out engine mounts.

If its IRS I would look at the bushes there, if perished or floged out, they can walk a bit and generate noise, if live rear end, upper and lower control arms may be the culprit.

It could also be a dry bush creaking away too? Just a few different things to look at.

Does it sound like a knock on the body or chassis? of is it dampend a bit?

Cant be suspesion because it does it at a complete standstill.


It can still be IRS mounts or control arms, when the car sits idle with the engine running, if a worn bush is preloaded the engine vibration can make things move enough to creak, but clunk is a different issue.

Out of interest have you checked your drive shaft bolts?

It can still be suspension even at standstill. stuff still moves.

OP says loud clunk from rear.


Yep, advice still stands. relisticly there is bugger all componetsto actualy check in the rear of a falcon.

 

_________________

Image

I have a car.

Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:45 pm 
Stock as a Rock
Offline
User avatar

Age: 25

Posts: 111

Joined: 24th Sep 2005

Gallery: 1 images

Ride: NA Fairlane

Location: Melbourne
VIC, Australia

without hearing the clunk itself will be hard to help much.
Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:47 pm 
Stock as a Rock
Offline

Age: 27

Posts: 133

Joined: 10th Aug 2008

Ride: Falcon AUII

Location: Gold Coast
QLD, Australia

nalane wrote:
There are no moving parts at the rear of the car at a complete stop except the fuel pump. When I put my ltd in neutral all the rattles go away, and I think its because of the faster idle. When my car warms up, about 15 to 20 mins, the S5 in the tranny plays up and the clunk causes a resonance through the chasis, but does not do it at a stop.
I think we are going to need more information to solve this one.


More details huh?.... I'm currently at uni so I can't check any of the suggestions till I get home tonight. To me the noise sounds like its coming from the exhaust, But I'm almost 100% sure its not now that its been replaced and the noise is still there. To describe the noise some more its kind of like a loud rattle against the chassis I guess. Not sure what other details would help?...


dc_todd wrote:
Rear of car rules out engine mounts.

If its IRS I would look at the bushes there, if perished or floged out, they can walk a bit and generate noise, if live rear end, upper and lower control arms may be the culprit.

It could also be a dry bush creaking away too? Just a few different things to look at.

Does it sound like a knock on the body or chassis? of is it dampend a bit?


How does one check for wear on the bushes?


nalane wrote:
There are no moving parts at the rear of the car at a complete stop except the fuel pump. When I put my ltd in neutral all the rattles go away, and I think its because of the faster idle. When my car warms up, about 15 to 20 mins, the S5 in the tranny plays up and the clunk causes a resonance through the chasis, but does not do it at a stop.
I think we are going to need more information to solve this one.


This sounds very similar to my conditions besides the fact my noise only occurs when slowing down or at a complete stop.

dc_todd wrote:
nalane wrote:
dc_todd wrote:
Rear of car rules out engine mounts.

If its IRS I would look at the bushes there, if perished or floged out, they can walk a bit and generate noise, if live rear end, upper and lower control arms may be the culprit.

It could also be a dry bush creaking away too? Just a few different things to look at.

Does it sound like a knock on the body or chassis? of is it dampend a bit?

Cant be suspesion because it does it at a complete standstill.


It can still be IRS mounts or control arms, when the car sits idle with the engine running, if a worn bush is preloaded the engine vibration can make things move enough to creak, but clunk is a different issue.

Out of interest have you checked your drive shaft bolts?

It can still be suspension even at standstill. stuff still moves.



How do I check the drive shaft bolts?




BTW, thanks for all the replies guys, much prefer discussing this with you guys than with my 'quality' mechanics...

 

_________________

....what goes here?

Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:51 pm 
Getting Side Ways
Offline
User avatar

Age: 28

Posts: 4326

Joined: 30th Oct 2006

Gallery: 18 images

Ride: Envi EF

Location: Grafton
NSW, Australia

Back to engine mounts - could easily be them as there is no load on the motor when in neutral so the exhaust doesnt twist.
Put it in drive, motor loads up, pulls to one side and the exhaust moves as well, hitting on the rear.

It should be pretty obvious though, just follow the exhaust and see if there are any scuff/rub marks on it or the body where it runs.

 

_________________

>>>EF Futura T build<<<

Top
 Profile  
 
 
 Post subject: Re: Mystery Noise
Posted: Fri Apr 23, 2010 1:52 pm 
Stock as a Rock
Offline

Age: 27

Posts: 133

Joined: 10th Aug 2008

Ride: Falcon AUII

Location: Gold Coast
QLD, Australia

krisisdog wrote:
Back to engine mounts - could easily be them as there is no load on the motor when in neutral so the exhaust doesnt twist.
Put it in drive, motor loads up, pulls to one side and the exhaust moves as well, hitting on the rear.

It should be pretty obvious though, just follow the exhaust and see if there are any scuff/rub marks on it or the body where it runs.



Will jack it up and check when i get home.

 

_________________

....what goes here?

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 1 of 2  [ 23 posts ]  Go to page 1, 2  Next

Who is online

Users browsing this forum: No registered users and 15 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

 

 

It is currently Mon Dec 18, 2017 10:52 pm All times are UTC + 11 hours

 

 

(c)2014 Total Web Solutions Australia - Australian Web Hosting and Domain Names