~2000-3000 rpm rattle on decelleration driving me insane

maxwolfie · Postby **maxwolfie** » Tue Jan 24, 2006 8:42 am

Hi guys,

I've had this *really* bad rattle (I.e. you can hear it from 50 metres away!!) since I bought the car - It sounds like a metal on metal sound..... Now, I thought it was the secondary heat shield (i.e. the shield that goes over the 4-[2]-1 part of the stock headers.. But AFAIK it wasnt.. There was a flap of loose metal there that was coming away, so I just ripped it off. But that didnt help!

Any other ideas?

It only does it while decellerating, so you can imagine how annoying it is when I'm rolling up to lights or coming to a stop in second gear (which happens every minute)

Please help!

Bevan · Postby **Bevan** » Tue Jan 24, 2006 9:58 am

I have the same sound in my NB8B but it's also whilst accelerating between 3000-5000rpm and also on deceleration in this rev range. Will get under the car and into the bonnet on the weekend and let you know how i go.

JBT · Postby **JBT** » Tue Jan 24, 2006 10:01 am

Could it be rocks in the catalytic converter due to breakdown of its internals :?:

maxwolfie · Postby **maxwolfie** » Tue Jan 24, 2006 10:01 am

Cool, I think I'll go to my hardware shop and buy 6 hoseclamps - 2 for each side of the cat, 2 for the secondary heat shield up the front on the middle of the headers..

And the last 2 for the exhaust hanging points at the rear.. At the moment I have those rubber-type over hanging things there, and they are wobbling the entire exhaust around. Maybe I can replace these with actual hoseclamps or would there be something better for this application? I'm afraid it will make it move around more! The exhaust is a little wobbly I have noticed!

maxwolfie · Postby **maxwolfie** » Tue Jan 24, 2006 10:27 am

JBT wrote:Could it be rocks in the catalytic converter due to breakdown of its internals

Any way to get these out possibly? Perhaps some spirited 7000 rpm driving for a while? :mrgreen:

Jokes

JBT · Postby **JBT** » Tue Jan 24, 2006 12:29 pm

maxwolfie wrote:At the moment I have those rubber-type over hanging things there, and they are wobbling the entire exhaust around. Maybe I can replace these with actual hoseclamps or would there be something better for this application? I'm afraid it will make it move around more! The exhaust is a little wobbly I have noticed!

The designers cunningly put those there to insulate the interior from a whole lot of vibes and noise. Mess with that at your peril. Do they need to be replaced?

maxwolfie wrote:Any way to get these out possibly?

New cat is about the only way AFAIK.

maxwolfie · Postby **maxwolfie** » Tue Jan 24, 2006 12:59 pm

JBT wrote:
maxwolfie wrote:At the moment I have those rubber-type over hanging things there, and they are wobbling the entire exhaust around. Maybe I can replace these with actual hoseclamps or would there be something better for this application? I'm afraid it will make it move around more! The exhaust is a little wobbly I have noticed!

The designers cunningly put those there to insulate the interior from a whole lot of vibes and noise. Mess with that at your peril. Do they need to be replaced?

maxwolfie wrote:Any way to get these out possibly?

New cat is about the only way AFAIK.

Damn! It's rather hard to tell if it's my cat or something *after* the cat, or a shield somewhere..

Ahh.. dammit..

rain902 · Postby **rain902** » Tue Jan 24, 2006 8:14 pm

maxwolfie wrote:Any way to get these out possibly? Perhaps some spirited 7000 rpm driving for a while? Jokes

cut it off, shake it up and down. dont bang it against anything. weld it back on.

could also be a fracture of the monolith itself - i had the same noise in my work van, until the monolith collapsed and jammed my exhaust, robbing me of the ability to do anything but idle....

*new cat*

MxJadeMonkey · Postby **MxJadeMonkey** » Tue Jan 24, 2006 11:15 pm

ok max i have the exact same noise and have done for 1.5 yrs now and have tried all but a new bloody car to get rid of it, i replaced the cat, i ripped off nearly all the heat shiels, took of the stone guard, changed the headers, had it up on the hoist ten times and cant find it, i recently imploded my gear box so i got one from a mate really cheap and wacked that in with only 50 thou on the box half the rattles went away for a wahile but now there back, hehe not as loud but they are there, i am waiting on a new exahuast and high flow cat now and will let you know if anything changes, if you find the noise let me know asap, hehe haha. good bloody luck buddy.

maxwolfie · Postby **maxwolfie** » Wed Jan 25, 2006 7:53 am

MxJadeMonkey wrote:ok max i have the exact same noise and have done for 1.5 yrs now and have tried all but a new bloody car to get rid of it, i replaced the cat, i ripped off nearly all the heat shiels, took of the stone guard, changed the headers, had it up on the hoist ten times and cant find it, i recently imploded my gear box so i got one from a mate really cheap and wacked that in with only 50 thou on the box half the rattles went away for a wahile but now there back, hehe not as loud but they are there, i am waiting on a new exahuast and high flow cat now and will let you know if anything changes, if you find the noise let me know asap, hehe haha. good bloody luck buddy.

Meh, I got under my car last night, one of the flange bolts was loose near the rear.. Tightened that up and checked the rest out but it didnt do anything.. I'm pretty sure its coming from the rear somewhere.....

JBT · Postby **JBT** » Wed Jan 25, 2006 8:08 am

Check for loose baffles in the rear muffler. Also have a good check around the pipes/mufflers to make sure the system isn't rubbing on something when the drivetrain shifts slightly during deceleration. There should be some witness marks if it has been rubbing. You may need it up on a hoist to have a good look.

maxwolfie · Postby **maxwolfie** » Wed Jan 25, 2006 8:58 am

Cheers mate, I had a REALLY good look last night, and I can confirm that nothing is rubbing at all!

I'm guessing one of the baffles are loose inside.. I suppose there is no way AT ALL to fix this??

JBT · Postby **JBT** » Wed Jan 25, 2006 11:56 am

maxwolfie wrote:I'm guessing one of the baffles are loose inside.. I suppose there is no way AT ALL to fix this??

Only with a new muffler I'm afraid

Babalouie · Postby **Babalouie** » Wed Jan 25, 2006 12:05 pm

maxwolfie wrote:Cheers mate, I had a REALLY good look last night, and I can confirm that nothing is rubbing at all!

I'm guessing one of the baffles are loose inside.. I suppose there is no way AT ALL to fix this??

Give the muffler a good swift kick...can you hear it rattling?

maxwolfie · Postby **maxwolfie** » Wed Jan 25, 2006 12:33 pm

Babalouie wrote:
maxwolfie wrote:Cheers mate, I had a REALLY good look last night, and I can confirm that nothing is rubbing at all!

I'm guessing one of the baffles are loose inside.. I suppose there is no way AT ALL to fix this??

Give the muffler a good swift kick...can you hear it rattling?

Cant hear anything - sounds fine when i kick it when the car is off.. something only start rattling at idle and other certain rpms. .