I was just wondering what it sounds like when the cat goes, cos my car is making a loud rattle like noise whenever the revs increase or decrease and its coming from right underneath the firewall.

from what i've read you just knock on the cat to see if you can hear a rattling noise (honeycomb broken away)
or you get a rotten egg smell

Well if its a goner its probably a good excuse for a new zorst system.

it may be a broken engine pipe.... if i hear it i'll be able to tell you, i have had it happen to me twice already....

I was just wondering what it sounds like when the cat goes, cos my car is making a loud rattle like noise whenever the revs increase or decrease and its coming from right underneath the firewall.

Should sound a bit quieter, no more meows in the middle of the night.

The burning might be a minus though.

that is exactly the sound I had when my catalytic converter was stuffed.

and I was also getting the rotten egg smell after I parked in the garage.

cheers,
.wook

I did notice smell after i first heard it and got it home but didnt take much notice of what it actually smelt of. Driving it to tafe was a bit embarasing today, sounds like a couple peices of iron sheeting vibrating against each other. I guess if I havent had it looked at by thursday ill get a couple of u fellas to check it out at the meet.

it may be a broken engine pipe....

What is an engine pipe? Is it part of the exhaust manifold?

have a look at the heat shields also.. the bolts go incredibly rusty and break over a period of time.. or the fiberglass matting insulating them falls out etc and the sheild rattles against the pipe..

same can be said for the heat shiled on the cat (minus the fiberglass)

i noted a pretty significant gain in fitting a high flow metal cat to mine.. one of those garunteed not to restrict flow ones.. cost around $250 trade for a new 2.5" stainless one..

only downside is it makes like a whistle noise when you sink your boot in it!

Had a massively loud rattle on my old Camry (it was one of those embarrassing to drive ones), turned out it was just one of those tightened clips bolted over the joins in the exhaust system, I just ripped it off. I say put your car up and have a look for loose stuff, give it a few revs to to find the exact place the noise is coming from. At least you'll eliminate all the cheap easy fix stuff, and if you can;t locate it, then go in and get it looked over.

Problem is i havent got anywhere to put it up to have a look. I think ill have to get it looked at friday or saturday if we cant find the cause on thursday night.

c0ck one leg up on the gutter ;) the bush mechanic way to get under your car without a jack

c0ck one leg up on the gutter ;) the bush mechanic way to get under your car without a jack

That was uncumfortable BEFORE i got the car lowered. And i aint no small guy so that would be a bit of an effort now.

reverse it up the curved edge on your driveway, takes the height of the gutter out of the equation :D

hydraulic jack and some axle stands are cheap from super-cheap these days, invest in them for when you really need them! Rattle the cat from side to side should be enough to tell if its fubar'd. It will rattle like crazy if the ceramic innards are shot

Ill get my lil bro under there :badgrin:.

Ok i got my bro under the car n he was shakin it a fair bit but ther was no rattling noise. He was shaking it enough that the only noise we could here was the pipe hiting the body of the car. Guess it must be something else.

What is an engine pipe? Is it part of the exhaust manifold?

engine pipe is the pipe that links the front and rear exhaust manifold into 1 pipe before going into the cat.

I have an engine pipe and a CAT for sale! PM me if it comes to that.

engine pipe is the pipe that links the front and rear exhaust manifold into 1 pipe before going into the cat.

So if it turns out to be the engine pipe (which its lookin like it is) will getting extractors fitted solve my problem? I remember reading a post of yours sayin this was solution you used and i was goin to get extractors over the coming months any how.

Usually it goes MEOW???

Seriously, there is usually little more difference to the sound, the rotten smell is normal. Best thing to do is grab a pair of gaskets from a parts place, get under it, soak the 4 nuts in wd40 and take it off. Is simple and you will then see if the core looks ok.

Cats do wear out, like anything