Cat need replacing?

[sam55]

My exhaust has been blowing for some time, and I was planning on getting a Yozza straight away but now I'm waiting for the new system that's coming out next year. Just today I was driving the car and noticed the blowing has become much louder, as well as the section immediately below the gear stick (where the cat is) makes a blowing sound when I give it the beans and the revs climb. The blowing isn't steady, but sounds like it's coughing.

Could the cat need replacing too? Bearing in mind the exhaust is the original and the car's done nearly 80k. I can't get under the car now as it's pitch black and I'm working all day tomorrow.

If it is the cat, what is best replacement cat? I know the Renault system is muchos ££ and a de-cat isn't an option for me.

Cheers

 

[guysy]

I would guess a sports cat, or a replacement second hand cat off a low mileage clio

I would think you just need a new genuine cat joining kit, thats the first thing to try there about £25 from Renault, and Renault are the only place to get them from ive read a few times, not aftermarket.

 

[sam55]

I was thinking that, but would a sports cat like the KTec one for example be worth it?

 

[guysy]

Have you taken it to an exhaust place first ? mines blowing too... i edited that out now because im not sure where mine is blowing from,

But a new gasket and fitting kit is the cheapest thing to try first. unless youve got white smoke coming out of the exhaust your cat is probably fine and hasnt collapsed inside.

 

[sam55]

Funnily enough my dad is a mechanic but he's very busy with work at the moment (everyone's cars are breaking down lol) and I'm working over Christmas so a new system isn't out of my budget. I just wanted to see if I could determine the likely problem, but yeah I agree the cat shouldn't be the problem, I just hadn't ever heard a blow from that far forward of the system before, normally it's just nearer the back.

I think maybe the seal between the cat and exhaust has gone, the exhaust mounts are very weak too so assuming the whole system is flexing a lot when I'm accelerating so that's probably not helping

EDIT: Oh and forgot to mention, I remember my dad mentioning about cats breaking up inside and rattling, but still partially working so not releasing lots of white smoke. So that's what got me thinking about the cat needing replacing

 

[guysy]

Could be mate, tbh im not a mechanic im just passing on what i know, someone else might be able to help but hopefully your cats fine.

If your working treat yourself to a new exhaust, hangers and OEM fitting kit i guess!

Going to be doing the same after xmas will probably be getting an RS192 exhaust, although my drivers fronts developed a clicking now so will have to fix that first :dapprove:

 

[sam55]

Bloody Renault exhausts are crap. I'm definitely getting new hangers, and I'll look more into the cat. Don't fancy throwing away £200+ on a cat if it's not needed obviously. I have a list of issues to sort on mine, many heat shields seem to be barely hanging on ha.

The RS192's look very nice, I was set on one until I heard a mates Yozza!

 

[James28]

Sounds like it could be the Manifold > Cat gasket. You can get the fitting kits from Renault with new spring bolts for $27
Put your hand on the joints with it idling to feel for any air, help tell whether its the cat itself or the joins.

 

[sam55]

I'll give that a go, I'll get the car up on the ramp and hopefully can determine what it is. Thanks!

 

[jobac]

Sounds very similar to mine, I was convinced that it was the cat that had blown but turned out to be the clamp that had rusted and broken. Cheap fix in the end. Hope yours is the same.

 

[Tony Hunter]

The cats tend corrode where they join the manifold,check this area first.

 

[sam55]

Cool cheers guys, hoping it's just simple like that as the problem was almost unnoticeable on my commute today. Drove slowly and light footed and the car sounded fine tbh, it's only noticeable under load so thinking it's just the gasket/join that's needing replacing.

 

[sam55]

Good news, got the car up on the ramp and found that the centre silencer (the one the connects to the cat) is the cause of the rattle, it's cracking on the join to the pipe, and the internals are rattling. The cat sounds fine and so I think it's just the exhaust that needs replacing. Really needing that new system from BTM to be for sale asap!

 

[guysy]

Good news mate, I replaced my V clamp on the end of the cat to mid silencer, its made things a lot better, however i still have a horrible rattle noise when cold and im off the throttle....

Aiming for the RS192 after xmas, and will attempt to fit it myself i think.

 

[sam55]

Could be the same issue as mine, the internals of the silencer maybe. The RS192 does away with that silencer IIRC so that could cure it!

Yeah that's a good shout, I think I'll change all bolts, springs gaskets etc when doing the exhaust. Can't wait to throw this old standard system in the bin!