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Discussion Starter · #1 ·
I'm getting more and more irritated with the 2000rpm tinny rattle that I am pretty sure comes from the rear left wheel on my 2.5 Arizona. Of course I can change gear/revs to stop it... Or Speed up or slow down but the metallic rattling (even briefly) spoils the smooth engine sound. Funny how your ears become obsessed with the tiniest details!
When I had new pads fitted it didn't cure the problem, I'm pretty sure they weren't mazda parts but the garage is very competent, and the brakes are undoubtedly mechanically sound.
It's just the revs and bumpy roads that causes the vibration.... Any suggestions?
 

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Barnardo, I have no experience of the Mk 2.5 but the brake pads are similar to the Mk 1 and there is a built-in ringing noise in the disc brake pads when they are worn... however, that does not explain the 2,000 rpm bit.

Are the pads worn?
 

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Discussion Starter · #3 ·
The pads aren't worn in fact they are new. The sound isn't that warning sound but more a shaking coat hanger sound when the brakes aren't being used.
 

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Token Yank
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The pads aren't worn in fact they are new. The sound isn't that warning sound but more a shaking coat hanger sound when the brakes aren't being used.
As with Martin, I have no experience with the MK2, but on my MK1 there were a bunch of clips designed to eliminate rattles, the obvious, are these all properly in place?
 

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2015 Mk4 (ND) 1.5 SEL NAV Ceramic Metallic
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The pads aren't worn in fact they are new. The sound isn't that warning sound but more a shaking coat hanger sound when the brakes aren't being used.
As with Martin, I have no experience with the MK2, but on my MK1 there were a bunch of clips designed to eliminate rattles, the obvious, are these all properly in place?
I would agree with Wrangler on this.

Also consider the exhaust heat shield, which is a common source of the "tinny" sound you describe and would explain why it is rpm dependant.
 
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Token Yank
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The pads aren't worn in fact they are new. The sound isn't that warning sound but more a shaking coat hanger sound when the brakes aren't being used.
As with Martin, I have no experience with the MK2, but on my MK1 there were a bunch of clips designed to eliminate rattles, the obvious, are these all properly in place?
I would agree with Wrangler on this.
Also consider the exhaust heat shield, which is a common source of the "tinny" sound you describe and would explain why it is rpm dependant.
The heat shields would be my second guess. Does the rattle go away when the brakes are lightly applied. If so, I would be pretty sure that the problem is indeed in the brake system. If not, I would check the heat shields.
 

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I had a catalytic converter come loose inside its housing on a Focus. That gave a very annoying metallic rattle sound at certain rpms. Accelerating and then backing off would also cause the noise.

The failure was down to driving through a deep puddle. The thermal shock separated the catalyst element from the case.

It meant replacing the unit but luckily Ford stood the bill as the car was only a few months old.

That rattle sounded as though it came from the rear but was actually close to the rear of the engine. Sound travels in strange ways.

Have you been through any deep puddles or banged the exhaust?

Just a thought.
 

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Discussion Starter · #8 ·
That's a fair amount to be thinking about! Thanks everyone.
An mx5 specialist gave the underside a few thumps to check for rattling when I asked him previously, so I have been assuming the brake is most likely.

I haven't looked myself to see if all the clips are there yet, I am not experienced in removing wheels etc so I will have someone check when possible, and I am aware the Mazda parts include clips that other brands don't. That would be a neat solution.

When I press the pedal the rattling stops, but only when it's enough to decelerate so I'm not sure if that proves anything.

I don't think the sound happens when revving in neutral. Moving along especially on a bumpy road or uphill at 2000rpm gets the vibration going. Never happens at higher revs!
 

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Discussion Starter · #9 ·
Update/ now I don't think It is from the brakes

With the help of my sister we worked out that it was the exhaust unit that does the vibration rattle when the revs get to 2100, when you press up on the ( warm) unit it muffles the vibration, pulling it down a little makes it louder. Sounds like I am getting somewhere!
 

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Good luck!

Something been knocked or moved? maybe a rubber hanger past it's best?

I had a similar thing once on one of my previous cars - it was the metal trim on the end of the exhaust, it was a right pain to locate!
 

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Had a similar noise on the LE until I fitted a new rear heat shield at the same time I installed the new stainless exhaust system - thereafter no more 'tinny rattle' . Try the same exercise on the heat shield as you did on the exhaust and this could well confirm the problem .
 

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Aedificantium in viridi Apparatus
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I'd agree with all of the above, the idea of getting an RPM related noise from the brakes doesn't really make sense as they are pretty well isolated from the engine. My first stop would have been exhaust right away, as has been suggested anything from a loose or corroded heatshield to a loose cat through to the internal baffle in the system either come loose or again corroded would be my first three ports of call. Hopefully something very simple like the heatshield is to blame.

Let us know when you find the culprit, all good info to have stored away on the forum.
 
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Discussion Starter · #13 ·
I've driven from the garage along bumpy
Roads and revved in the rattle/ buzz zone and everything seems ok! The engineer told me ( and I'm trying to get this right for you all) " the clamp that holds the silencer to the spigot/sensor had come loose and needed to be tightened up" does that make sense?
 

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Token Yank
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Barnardo, it makes perfect sense that something was loose on the exhaust system. But as someone said before, we are two people divided by one language. I know silencer = muffler; but I don't know spigot/sensor.

I really am responding because I would like to know.
 
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Aedificantium in viridi Apparatus
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Barnardo, it makes perfect sense that something was loose on the exhaust system. But as someone said before, we are two people divided by one language. I know silencer = muffler; but I don't know spigot/sensor.

I really am responding because I would like to know.
I also doubt very much if it was an Engineer that gave you the rather odd description of what the rattle was, much more likely to be a mechanic or technician. Just a little pet hate of mine seeing the term Engineer being misused so apologies if I seem a bit pedantic about it.

I am a time served mech fitter, a four year apprenticeship along with four years of college work took me to this level and I consider myself a highly skilled individual for having this qualification.

It took me a further five years of college work to attain my proper Engineering qualifications that allowed me to get off the tools and do proper Engineering including design work, project management,reliability and condition monitoring of heavy rotating plant, there is a world of difference between being a fitter, mechanic or technician and being an Engineer and as such a properly qualified Engineer's worth is often diluted. This has come about because anyone that can use tools in their trade will very often call themselves Engineers rather than use the proper term for their trade i.e gas fitter, pipe fitter, car mechanic, plant mechanic, electrician etc.

Again I apologise for the apparent nit-picking, I am equally proud of being a proper highly skilled mech fitter having served a very rigorous apprenticeship to gain that trade and then to apply that trade in a coal fired power station for 16 years, maintaining, repairing and installing all manner of plant as I am of taking a further five years of college work to attain my Engineers qualifications then being fortunate enough to apply many of the skills learned and indeed learn a whole lot more when applying them. I just hate seeing the term Engineer being used generically for anyone who can use a spanner.

I am guessing that there has perhaps been an oxygen sensor come loose in the exhaust, there are only two sensors on the system, one pre-cat and one post-cat, the description that your mechanic has given is a bit woolly to say the least but the main thing is that you are now running without the buzz, thanks for the feedback Barnardo.
 
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Token Yank
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I think it gets down to lack of pride in honest work, and a need for some folks to feel self important. I was never very sensitive about title, as long as I was paid.
 

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Discussion Starter · #18 ·
Thanks for the analysis, any mis quote is down to
my non technical memory rather than the mechanic I'm sure. He did talk about a clamp though and something about springs tightening it up again.
 

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Aedificantium in viridi Apparatus
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Same as Dennis but for me it is just the correctness of the description, as a fitter for example, I would never be expected to have the knowledge to design for example a complex pipework system that would deliver pumped fluid from a source at a pressure of x and a flow rate of y. I would be expected to do the installation work, bent thee pipes and use the materials in the most economic way. As for pipe sizing, pump sizing and choices of materials to cope with a specific corrosive medium, the correct valving to use etc,that is the remit of an Engineer and the reason they get paid (allegedly) the big bucks. It isn't a title thing at all, merely a correctness in the use of the term.

I wouldn't call a chef a baker, I wouldn't call a cabinet maker a joiner, nor would I call a brain surgeon a nurse, yet Engineer gets bandied about so incorrectly so often, as I say, it dilutes the worth of years of extremely hard graft to gain the relevant qualifications to correctly be termed an engineer.
 

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Aedificantium in viridi Apparatus
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Thanks for the analysis, any mis quote is down to
my non technical memory rather than the mechanic I'm sure. He did talk about a clamp though and something about springs tightening it up again.
The main thing is that you are sorted, there is nothing worse than a noise coming from the car that you don't know what it is. The mind starts thinking along the lines of is it a loose heat shield or is it something serious within the engine about to let go.
 
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