horrible noise underneath car, possibly the cat?

[lufkin]

Just got home last night after a big drive when i slowed down, noticed car making a terrible noise, sounded like a pulley was shitting itself, took it to parents place to see if dad had any ideas as i couldnt find anything, he reckons it isn't coming from under bonnet and upon me listening again i agree, but he thinks it sounds like its inside the exhaust, i got on trolley and got under car, sounds like its from around the cat, cant see it vibrating anywhere, im wondering could the cat be stuffed and would it make a rattling sound? the cars on gas, and some people have told me gas can kill the cat converter, not sure if any truth is behind it though, any ideas?

[graham7773]

According to a couple of lpg installers I know and just about every cabbie in Australia, lpg is safer than petrol for your catalytic converter. As for a rattling in your cat, that is what happens when your converter dies. The center material collapses and rattles usually caused by running rich or with spark plugs failing allowing unburned petrol to saturate the catalyst which destroys it.

[lufkin]

According to a couple of lpg installers I know and just about every cabbie in Australia, lpg is safer than petrol for your catalytic converter. As for a rattling in your cat, that is what happens when your converter dies. The center material collapses and rattles usually caused by running rich or with spark plugs failing allowing unburned petrol to saturate the catalyst which destroys it.

i know people will jump on here and advise against which is ok because i sort of am too, but till i get the car booked in, will be ok just to bash the cat out? or better yet take it off and see if shit falls out of it so i can confirm its the problem

[danja]

A cat in your exhaust is bound to make a horrible sound, I'd call the RSPCA.

[Tree cutter]

Just unbolt the cat and tip the broken bits out through the front then bolt it back on. Hopefully you will get a bit more use out of it this way.

[graham7773]

check to see if the neighbours mog is ok

[VT Owner]

Isn't the horrible egg-fart smell the first indication when the cat converter fails? Do you get this occasionally?

[lufkin]

no smell, dont think i have heard of that one before, my gf farts enough in the car anyways, probably blends. anyways i just took the cat off, and sure enough shit fell out looked like a earth quake happened inside, ive spent the last hour bashing it out, time for lunch now will put back on car and see if the noise is gone, then heading exhaust place here to get extractors and high flow cat, i already have a redback 2 1/2 cat back system anyone know of a good combo of extractors? im looking at sound, ive realised the calais is too fat and heavy with a stereo and what not to worry about performance lol

[lufkin]

well bashed it out, car still makes same noise wtf, to describe it more, you know when say you are on freeway and big gush of wind hits hard enough to actually push through your seals, it sounds between air rushing in and a pulley about to die,, but its only around 1500-2500 rpm then after that its fine and when i lift bonnet cant hear it at all, but can hear it from under car and seems like around centre. any other ideas, now im up for a new cat converter and that wasnt the problem lol ohwells

[vt s]

ive known vs gearboxes to make a similar sound due to the pan being so shallow but i think the problem was resolved after the vs, idk maybe someone else has seen this in vt not sure.

[graham7773]

VT owner, the rotten egg smell you mention is the smell of a working catalytic converter. A lot of new cars smell like that

[Tree cutter]

Could a piece of your cat converter be stuck inside your muffler.

[lufkin]

Could a piece of your cat converter be stuck inside your muffler.

NO and thats simply because i dont want it to be lol