I test drove both the R3 and the Sport RX-8 yesterday, and even took one home for an extended test-drive over the weekend. On both cars I heard a pretty noticeable rattling noise when I have the engine above 6k rpms (in any gear). It sounds like the noise is coming from behind the glove box. I have since read that this noise is often described as MIAC (marbles in a can). Today I drove two other RX-8's at a different dealership and I didn't notice this noise in either car. I have since ran my loaner to empty and filled up with premium (in case it was a fuel issue), but the noise remains. The video below shows the sound I am referring to. How common is this noise in RX-8s? Is this something any owner should expect to hear? I really enjoy the car otherwise and would probably purchase it, but this noise is rather annoying if it is something that will always be there. Thanks in advance for the help.


Sound clip/video of problem: http://www.youtube.com/watch?v=bm3NcgTnmRk

Cause of problem: Too much coolant flow at high RPM

Solution: Have Mazda install "orifice, heater hose" to restrict coolant flow (P/N : F10061E09)

(thanks to Trubach and RX8pwnage for the fix, ASH8 for the diagram, CSRACER for the photo of the orifice, and MikeBusch2 for the photo of the hose)

 

Is that your video? I have not had such a sound so i would have to say its not normal...

 

I had a problem with that kind of noise in my R3. Apparently there is an issue with the coolent flow at high RPM. The dealer took a day to figure it out, and per the folks at Mazda HQ, they put in some sort of restrictor and that fixed it. Been totally fine ever since.

 

I have an 07 GT. If my car has been sitting for at least a day, I get a sound from the glove box, but it sound like liquid sloshing for me. I know its just the fluid in the heater core.

Now if you actually have the marbles in a tin can sound coming from in front of you, from the engine bay, then you have a blown engine.

 

MIAC on an R3? Hmm..

 

lol so much for 09's being problem-less

 

I had MIAC on my R3. It set in at 1200 miles. My dealership called mazda and mazda sent the restrictor valve to be installed all done under warranty of course. NO issues since, currently at 5.5k miles. Too much coolant flow at high RPMs per mazda.

 

The bad MIAC is detonation.

 

whatever it is, it is stopped by restricting the fluid to the core. Took my guy at mazda about 30 seconds for him to get out, pinch the hose and say "redline it". Woot no more noise! Im so glad my mazda people know their stuff!

 

Thank you so much for this! I printed out what you wrote and took it to the dealer. They ordered and installed the valve and the noise is gone. I am now the new owner of a 2009 RX-8

 

Does the same restrictor fix apply to pre-09 RX-8's as well?

 

yes

 

this sounds simple enough for a DIY.

I notice when I rev the car just in neutral, this sound does not occur with mine.
The noises only occur when accellerating.
Does this make sense?

 

I think I may be missing a piece of the puzzle here, but wouldn't restricting coolant flow make the average temperature of our engine hotter?

 

yes, exactly the same thing. What is the fix?

 

I have this same MIAC issue - i originally thought it was due to my cat being shot, which it was, but after i had it replaced, still the same issue. It sounds like its coming from the right side of the car, but i hear it towards the back, even if i step out of the car. I'm going to look more into this restricter fix, i'm wondering if that is the issue.

I do notice that its only when i step on the gas, but its not just at 6k + rpm.

would any of you know if a noise which i can only describe as sounding like a coffee maker at the end of brewing a pot (sort of an airy, gurgling, boiling sound) most pronounced at 23mph in second gear be related?

 

It comes from the glovebox on my car

 

also have this issue but only at 8k rpms+

 

welcome congrats on the new 8 have fun with her

 

I have this coolant noise too on new 09 R3, coming from behind the center console vents between 7-9k RPM. Trubach informed me of the restrictor fix they did on his R3. I haven't taken mine in yet, but it would be cool to get the part number of this restrictor and just pop it in.

 

Unfortunately I didn't get the part number as I had them fix it prior to me buying the car, therefor I didn't get any paper work on what was done. Sorry.

 

I test drove a brand new R3, had the same noise as my 06

 

So that's what MIAC sounds like! Good to know if I ever hear it in mine.

 

congrats on the new ride

 

Thanks, I am really enjoying it.