Metallic Rattling Under The Car

[sl33ek]

Ok

My car has developed a rattling sound coming from under the car and maybe towards the rear. Over about two months it got louder and louder and now I cant stand it anymore

It is a metallic vibrating sound, imagine a putting a metal ruler halfway off the edge of a table and flick it.

Its very noticeable outside the car as I've opened the door while driving to find out where its coming from.

So far I've ruled out:

Bodykit (removed pods and sideskirt)

rear rego plate- put padding behind it

Exhaust heat shielding, both in the middle and the back by removing it and putting padding in the gaps

Everything in the boot was removed including jack and spare wheel

Exhaust piping hitting the chassis - put a rubber grommet between the two

Tapping various panels under the car, none seem to be loose

Now, the rattle seems to come at around 1500-2500RPM in 1st, 2nd and a bit in third.

Once it starts rattling even if i take it out of gear or clutch all the way in it'll continue to rattle until it fades.

Cruising at 80km/h is fine, only when accelerating to it, it rattles.

I've done a search, It looks like it could be the cat? but surely wouldnt that sound like a metal bucket full of marbles instead of a rattle?

Could be the resonator? - what is that anyway?

Loose body panels? - it wont explain why it happens only between 1500-2500rpm

I'm taking it to the exhaust shop this weekend to see what they think, before then has anyone had this problem and how did you fix it if you did?

[BEN 0]

hey dude i had a rattle once turned out i had a rock stuck in between my rear brake rotor and rotor surround. it sounded terrible like my exhaust had fallen off and was scraping on the bitumen.

you could try taking off your wheel closest to where the noise is and with a light kept behind the brake rotor then if there is a rock there use a coat hanger to get the barstard out

hope this is ya problem

[sl33ek]

Thanks Ben I'll add that to my to do list too this weekend

I just want to add that the rattle starts at 1500rpm and can last up to a minute at a time, but usually lasts until i get up to cruising speed. Not all the time, just most of it

[rd-runr]

Hop under ur car and hit the cat with the palm of ur hand. If it rattles from within the cat, theres ur problem!

[gel]

I had the exact same problem few years back with my previous car.

Had an aftermarket zorst and the muffler gave in...

The metal tubular mesh inside came off and was rattling inside the muffler. It was only audible at certain rev ranges especially idle and lower revs. Crusing is fine.

As rd-runr said, give it a fair whack with the palm of your hand and you'll hear metal bits inside...

[lingeringsoul]

I had a problem with rattling whne I let off the throttle...........................turns out, the rear wheel nuts were loose and that fixed the problem right up

[siksII]

it may be the cat. try shaking the cat around and might hear lose bits which would cause a rattle.

[sl33ek]

Thanks for the suggestions guys. I got it fixed ! Cant describe what a relief and how much better it is without that damned racket.

I took it to an exhaust shop today ready to fork out for a new highflow cat.

The guy bashed the cat but there was no rattle but I insisted on opening it so he did. Looked inside and it was perfect

So we poked around for about 20 minutes trying to figure it out when I found the culprit.

The handbrake cable fell out of its clip and hitting the base of the driveshaft (near the HICAS)

It looked a little worn so it was obvious its been hitting.

It was clipped back in and problem solved