I think that there are several different sounds being lumped together under this one category.
The vast majority of you are experiencing the AUX port valves rattling.

 

is there a way we can cheaply diagnose the cause ourselves before going to the dealer?

Yes I have thought it was with the S-DAIS as well because I can hear a switch 'click' sound come on ~6.5k and then the marbles begin. It's only coincidence that my sounds correspondingly happen with the aux port rpm range. I'm still betting it's the S-DAIS somehow.

What can we do? How do we stop the rattles??

 

This is the source of the noise !
I noticed this from day one, but I thought it was a heat shield problem.
https://www.rx8club.com/showpost.php...4&postcount=29

When I rebuilt my spare motor I came to the same conclusion that
MazdaManiac did 8 months ago.
https://www.rx8club.com/showpost.php...&postcount=219

There won’t be a cure for the current Aux Port configuration.
How loud the noise will be is dependent on how much carbon is built up around the Aux Port Sleeves, and some other factors.

By the way I think it's more of a Zinging sound. Not like air in the cooling system which is a gurgling sound.

And the aux ports are part of the S-DIAS.

 

I have the MS CAI from the very start when I bought the car. It already had it the first time I went up around the 7000 - 9000 rpm after my break in period...

The CAI is not the solution to the sand in blender sound. Mine sounds exactly like the infamous youtube video.

 

I agree there are probably several sounds being lumped together. In the case of my car, the metallic rattling sound is caused by the Catalytic converter - a piece of it broke off and is rattling around inside the resonator. Mazda is replacing the cat.

The interesting thing is with the fragmented cat the exhaust tips are clean inside right now, not black.

NOTE: my car 's engine was never flooded.

 

I've been off the board for a while (traveling a lot), but am back and active again. The shop called Mazda of North America about the sound. They're official line was that "it's normal" (I hate that answer) and it was indeed air rushing past the heater core. They said it can't be fixed but should go away with time. Uhhh, ok. That doesn't sound right to me. However, for no identifiable reason what-so-ever, it has been gone for quite some time. I've been using the same gas now but I don't know how or why that would make a difference.

-My sound is exactly like that of the You Tube video and it sounds like it's coming from behind or near the glove compartment. It gets stronger with higher revs and it doesn't sound like a rattling, it really does sound like fast bubbling or "sand in a blender". It can be felt in the passenger foot well on especially bad days.

 

For the last 6 months I have hard the same noises and lack of power. Recently i manually activated the SSV Actuater to its full movement a few times and found it loosened up. It was sticky to start with and after this I have not had the problem again. So how about someone else try this and see if it helps. May be the SSV valve is building up with carbon and sticking.

 

That is a technically incorrect definition, but the idea that the noise is the result of cavitation is very intriguing to me.

And if you want to know how I know that the definition is wrong, it is because I am an engineer at a pump company.

 

I have a rattle at very high rpms, only in movement, not when standing still and reving up. I think it's actually more apparent if there's some sideways movement as well. So I'm thinking it's nothing internally in the engine. Really annoying though as it hasn't been there before.

Less than marbles, sounds more like a plastic to metal rattle/thud.

 

Why not check your SSV valve on the inlet manifold and see if yours is jammed or sticky. It should move fairly freely when you turn it and spring back to the rest position. I'm curious if its the same problem I have.

 

Now to figure out where that is :P

Annoying with sounds, afraid there's something wrong and can't floor it.

 

ok has anyone found this sand in a blender sound? lol its getting bad

 

maybe this only happens on low mileage rx8 till they get older i dunno

 

Oh yeah. Because, you know, we engineer the car so that air rushes past the heater core, but after X number of miles air STOPS rushing past the heater core.

 

lol i know, i took my car to the dealer and they said give it time lol

 

Someone claimed they fixed the problem, yet cant show what parts actually failed?

 

Had my car for 2.5 years and it never went away. The "normal" thing is BS to me, if it's normal then why doesn't every RX8 sound like this?

 

Tolerance. If someone says something is normal in a manufactured product, but it doesn't happen in all of the products, it is attributable to manufacturing tolerance. Now, just because something is "normal" according to tolerance does not mean it is acceptable or potentially harmful to the machine. But the reverse is also true, you can't assume that it is harmful.

 

ok i dont understand why cant a dealer fix this, it does not sound good at all, im so tired of this, i took my car in and they said give it time, trying to blow me off,

 

Just found out that the first 30,000 or so (World-Wide) RX-8's of 2003-2004 did have the "ORIFICE" installed inside their Heater Hose.

The same one "some" Mazda Dealers are installing to stop this noise, when owners complain.

The Hose is the "Coolant Supply" line, at the Thermostat Housing metal outlet and Hose end joint.

Here is a Parts Pic showing where this orifice is installed at the factory.

It appears Mazda have not installed these on any 09 (Series II) either.

US owners have been complaining of this noise and this is the Fix to install the F100-61-E09 orifice.

At this stage there is No TSB, repaired ONLY if owner complains to their dealer.

It is a $5 buck part, but the installation is more involved (remove Battery) and some coolant loss when removing/replacing Heater Hose to install the Orifice inside the hose end.

If your Series 1 RX-8 was made AFTER December 1st, 2004, YOU DO NOT HAVE THIS ORIFICE INSTALLED.

APOLOGIES TO ALL...I got it Wrong and back to front....Silly Old Bastard I am!

The above info is now correct thanks to MazdaManic..

 

Mine was built in July of 2003 and it has always had this brass orifice insert.

 

very nice find and post ash..

beers

 

My Apologies J ...I got this wrong...I should of read the actual Heater hose info also, rather than just the "orifice" info, I viewed it as From 041201, in fact it was UP TO 041201 Production...sorry man.

From 041201 Mazda "Removed" the Orifice

 

Hi Scott...

My info has been corrected...I got it wrong...thanks to Jeff....

All the 30,000 (approx) S1 RX-8 made UP to Dec 1st, 2004 had the Orifice Installed..

AFTER Dec 1st, 2004 Mazda ceased to install them in ANY Series RX-8 since..

So, in some ways this is more of a revelation (call it what you want ), that Mazda removed these restrict-ors (whatever you want to call them), so MORE RX-8's, 2005,6,7,8,9 could potentially have these "noise" symptoms.....

NO wonder Mazda don't want a TSB on this???

 

Next question is WHY?

Why did Mazda remove them, Jeff says they are brass, anything to do with corrosion?

Or was, is there a problem with heater performance.

ANYONE..