crackerly noise

[beatjunkie]

ive got a mk1 clio 1.4s and when i hit 30,000-35,000 revs theres a really weird crackerly noise coming from probly near the catalytic converter!what ever gear im in it will do it in this rev range.

ive just had a ss exhaust fitted but this is only the back box so i dont fink it should effect it?any ideas is it the cat, because it sounds like something is stuck some where!how much should a new cat be cos mot is soon!

help!

 

[TheCake]

30-35,000 revs. nice.

 

[Daz]

30,000 revs? No wonder its crackling..

 

[Mole]

i had a problem with my backbox when i put it on my car, it was tapping up against the rear tow hook, now ive cable tied all the mounts to stop them from coming loose and pushed the backbox back so it sits just behind the hook.

as for cats, ive just bought a new one for £95 from http://www.buypartsby.co.ukwww.buypartsby.co.uk

but my car is still failing its MOT on emissions, but thats due to something else i think.

 

[beatjunkie]

aaah rite i got the revs wrong 30-35 still no one got any ideas?its not the backbox cos thats all sitting properly now!so i dont no!

probly still got revs wrong havent i?

 

[RobFenn]

Yep

 

[Daz]

Hehe, 3000->3500 revs.

Crackling noise, I dont have a clue.. someone will tho!

 

[Max172cup]

Well, could it be like on the 172, the 4000rpm rattle? Thats something to do with the heat sheild i have been told. Ive got a aftermarket exhaust on mine and it still has the old 4k rattle, i think its the heat shield vibrating at its natural frequency.

 

[beatjunkie]

well at least i got the revs thing sorted!

yeah it could be the heat shield ill have to have a look but what does a broken cat sound like?sounds like the airs not flowing properly really weird

 

[Dopey]

lol.......... sorry...... I read this as crackerly nose!!!

 

[beatjunkie]

any one else with other ideas had a look at the heat shield seems fine there is slight gas leaking from the down pipe to catalytic converter though at the join hardly nothing though

 

[JAY172]

what if you bash the cat with your hand(when its cold of course) do you hear a rattle from inside it?(poss cat breaking up). is the front pipe clear of the rear engine mount?

 

[beatjunkie]

ill hit the cat tomo morning and see if it does good idea!yeah all the pipes are clear of any mounts im sure of that had a look earlier.the cats pretty rusted over looks like its passed its time but i dont fink its been changed since the car came out the show room because ive got a well gd service history.cheers

 

[beatjunkie]

just went outside cat seems to be solid, now i havent got a clue,also when the engines idling theres a ticking noise coming from the air box?!

i love my noises dont i!

 

[JAY172]

is the exhaust blowing anywhere?

 

[MaLicE]

does it sound like some 1 is blowing a diggerydoo really loudly at 3000-3500 ??? if so and its a stainless system.. some of them sound like that... cheap grade ss and silencers...

 

[beatjunkie]

its blowing near the both ends of the cat and the cat looks pretty worn out its well rusty!its definitly coming from inside it there fore do i need a new catalytic converter any way of testing it?

 

[ViolentJ]

someones put rice crispies up your exhaust.

 

[JAY172]

take the cat off and have a look inside. is all the honeycomb looking centre present and secure? if it is then refit it and seal the flanges.

 

[beatjunkie]

is that an easy job then jay havent really done nuttin to a car except wiring up systems.both sets of nuts are rusted really badly so ill think ill replace them!how do you seal the flanges please?can you buy these are they like gaskets?

 

[JAY172]

just grind the bolts off and use new ones.refit using a slight bit of exhaust paste and fit new gaskets on each flange.

 

[beatjunkie]

so could just be a dodgy connection then cheers for your help, hope i dont have to get a new cat cos im trying to get some koni adjustables hopefully

 

[JAY172]

if it is knackered then you could get a decat pipe which is cheap and just make sure you find a cat before mot time.

 

[beatjunkie]

thats what i wanted to do but mot is at end of may so no point really im gonna try and get some prices on a cat i fink £100 was my best price last time on my old car!

i no u probly wont but as a long shot i want a suspension kit for my car and need to no the distance on the front suspension bracket i fink its around 54mm would this be correct for year?thanks again for the advice