Loud metallic rattle

[James17]

so I've just fitted a new catback and there's now a horrendous loud metallic rattle coming from the manifold area. Anyone else had this?

Will upload a video

 

[Jimmy]

I have a rattle from mine - Scorpion catback - that's been there since I had it fitted. Interested to hear what yours sounds like on the video, to see if it's similar. I wouldn't say mine is horrendous, more annoying. It only happens during acceleration up to about 3k revs - you can hear it most when I pass parked cars, or driving next to a wall etc.

The mechanic thought it was a wire fouling on the pipe, but him moving that hasn't sorted it. It's one of those that's quite specific when it happens, so probably hard to pinpoint on a test drive....

 

[Sean197]

When the flexis on the manifold start to go they do make a metallic rattling noise.

 

[bounds72]

Is the exhaust touching the diffuser??

 

[Micah]

I wouldn't say mine is horrendous, more annoying. It only happens during acceleration up to about 3k revs - you can hear it most when I pass parked cars, or driving next to a wall etc.

This is exactly what I get which made me think the flex's were on their way out. The manifold has been looked at by 3 different people since I've had the car and all have said it's not showing any signs of wear. It just wind me up wondering why it should sound so rough if it's fine - bloody Renault!

 

[sevenfourate]

....the noise is probably your eardrums



***Only happens at a certain revs, at a certain time etc ? ie: Is there any pattern to it ?

If you've just had it fitted - my bet is its touching something.

 

[James17]

Oh it's not coming from the rear of the car, it's coming from the front and is very loud at all revs. More so below 3,000. It's not the exhaust rattling it has to be more

 

[Kazumz]

Mine used to tap the diffuser heat shields.

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[Sean.]

I have a rattle from mine - Scorpion catback - that's been there since I had it fitted. Interested to hear what yours sounds like on the video, to see if it's similar. I wouldn't say mine is horrendous, more annoying. It only happens during acceleration up to about 3k revs - you can hear it most when I pass parked cars, or driving next to a wall etc.

The mechanic thought it was a wire fouling on the pipe, but him moving that hasn't sorted it. It's one of those that's quite specific when it happens, so probably hard to pinpoint on a test drive....

Have exactly this problem on the Mrs' car

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[Jimmy]

Very odd... Listening today, mine is more of a buzz, like it is catching on something, or perhaps a loose heat shield. It's really not that bad as it is very specific when it happens and only when on the move - it doesn't do it if I'm stationery and try to make it happen...

 

[Helpimonfire]

From speaking to Andy at Engine Dynamics, he was telling me that the pre-cat that's built into the manifold has a habit of rattling. I'd guess this could be your problem. It comes loose inside the manifold, won't do any harm from what I've heard though

 

[sevenfourate]

From speaking to Andy at Engine Dynamics, he was telling me that the pre-cat that's built into the manifold has a habit of rattling. I'd guess this could be your problem. It comes loose inside the manifold, won't do any harm from what I've heard though

Good shout Martin.

I've heard of this on many vehicles. I might have even had it occur to me once (Memory fails me right now).

"Some" people have of course gutted various cars cat's in order to visually pass a roadside test / MOT by leaving just the outer shell visible. On some cars i gather its not that hard to do either with a substantial enough ramming instrument ! So hardly surprising one or two work loose i guess.

Worth getting checked for sure.

 

[James17]

 

[James17]

 

[James17]

If you guys have had this noise before do let me know!

 

[tcw]

I had this. I thought it was the pre-cat falling apart. I replaced the manifold -> cat clamp, then the cat -> exhaust clamp (scorpion) with a mikalor clip. Done both up with an impact and I've never heard it since. I think the cat -> exhaust clamp was the one that sorted it.

 

[James17]

I had this. I thought it was the pre-cat falling apart. I replaced the manifold -> cat clamp, then the cat -> exhaust clamp (scorpion) with a mikalor clip. Done both up with an impact and I've never heard it since. I think the cat -> exhaust clamp was the one that sorted it.

Ok thanks, so hopefully it'll just be a few new tight clips and that's it?

 

[tcw]

Ok thanks, so hopefully it'll just be a few new tight clips and that's it?

Well - from my experience it did solve the issue so hopefully it's a simple fix like that for you. It's worth having a quick look at the pre-cat and the second cat once you dismantle everything. I think I bought a 63-68mm Mikalor clip - I could probably have gone a size down, as it's very very near the limit.

 

[Tutuur]

Funny thing is i have the exact same thing since a few weeks, not audible when cold or stationary, however when properly driven it does is at low revs (3000rpm).

Just took a look under the car, clamp is deffo still tight and leak free, didn't have anyone to mash the accelerator for me but i'm 90% sure it's the precat aswell.

Now to find the best way of getting rid of the innards!

 

[James17]

Well mine does it from every rev and just anytime haha and also one car has gone "missing" so I can rule that one out