throwout bearing rattle?
 

more so when my engine is cold i get this whirring/rattle type noise with the clutch out, if i press the clutch in it goes away. at the socal meet i spoke to i think it was disney destroyer about it and we walked over to his car and he started it up and it did the same thing.

i'm not sure it's the throwout bearing, but that's the type of sound it makes...i'm more familiar with a 4speed saginaw mated to a 350 smallblock and that's the kind of noise that makes me think to replace the throwout bearing.

so anyone else get this?

Re: throwout bearing rattle?
 

My Miata 6-speed and my wife's 5-speed have the same rattle. My pet theory is the gearbox input shaft bearing.

The service guys at Mazda South went back-and-forth with Mazda's tech line about it, but Mazda is adamant that it's "normal." You'll notice it's worse when you have the AC on too, for some reason.

I guess the RX-8 'box has more in common with the Miata's than we thought.

Re: Re: throwout bearing rattle?
 

nearly exactly the same unit with beefier shafts and gears for the increase in torque.

This is exactly what I heard on mine too. I picked mine up yesterday and I didn't noticed this until the car was in my garage. The enclosed area just made it more apparent. At first I didn't know WTH was making that sound. Clutch disengage = small whirling noise. Clutch engage = no noise. My friend, who's more technically verse, said it was the throw out bearing noise. I've never heard this on my Civic. But my friend's Corvette does the same thing, except it's louder.

Both my Miata and my RX-8 do this. It's apparently normal. It sounds much worse than it is.

J.

Ditto everything. Being not technically versed, is this anything to worry about or just normal operation? I first heard it in the garage but now that I'm attuned to it I notice it at stoplights, etc.

btw, I get a whirring but not a rattle.

well that sure makes me feel a lot better about it then. i don't really use a/c though unless i have passengers

I have it too. Thats normal, Ive had other cars with the same thing.

Any other wierd noises? I had addressed a few in another thread. 90 MPH rattle and some exhaust popping.

have it too (t/o bearing)
I get a funny noise when starting out / backing up or starting forward as turning, type of thing when first getting going. Hard to describe, almost like brakes were stuck just for a sec like when the rotors get that coating of rust after washing or rain...

That's your ABS going through its startup test.

I get that too, but only once when I first start the car and take off for the first time. It never does it again after that. I couldn't decide whether it was my brakes or clutch because it only happens when I get completely off the clutch and begin moving for the first time after it was started.

Really?

Good Duck is absolutely right.

The ABS runs a self test at start up and makes that "servo" noise. Its normal. You can almost feel it in your feet also

When the car starts or when you first begin to move it forward?

I have noticed it when you put it in gear and move forward....or backward.

OK, then it probably is the same thing I'm noticing as well. Hummm...where did you read that it was the ABS test anyway? Just curious in case other oddities show up I can look for a reference before coming here complaining (even though that is the only really odd thing I've noticed yet...except that the electric fan is louder than the engine lol).

I too remember reading about this brake system self-check somewhere - the Technical Highlights CD, perhaps.

I think it does it after you've travelled a few feet in either direction. Mine does it just as I ease on the brakes at end of my driveway - was a little disconcerting the first couple of times.

Boy, thank you so much for mentioning this. I felt it today for the first time -- before seeing this post -- and thought I had done something to the trannie. I had just started up, and was backing, when I felt a shudder. Never felt it again. This car is just full of surprises.

The throw out bearing noise will generally happen , if your car has the noise, all the time. About the only time you can hear it is in a quiet area with the stereo and blower off and just leave it in neutral and put the clutch in and out. The manual states to let the car idle for 10 seconds when starting - assume this means cold starts - but that may be for the ABS test and things to take place. I've been trying to let that happen while I roll out of the garage and close the door in the mornings.

The ABS self-test only occurred after the vehicle has moved. IMO, the suggested wait of 10 sec after starting and before moving is to let the oil reach normal operating pressure.

good theory
 

Good theory - but wrong. The oil won't reach normal operating temperature for about 10 minutes. I do believe the noise I hear when first moving could be something to do with the brakes. It seems to take place no other time than cold starts.

Driving away "thud"
 

Regarding sounds that occur when the RX8 first rolls, I certainly hear them and have been envisioning a couple of things. Symptoms are a "light thud" when first rolling backward out of my driveway, then a larger "panel whack" sound when I take off forward. I don't claim to know what they are, but here's my guess:

1) "light thud" = brake test
2) "panel whack" = a panel that closes the front air intake for a "fan cooling mode" is re-opening

I don't know if such a panel even exists b/c I haven't investigated, but my '88 Porsche 928 did this (and they're practically the same car... jk).

Re: good theory
 

The 10 seconds wait I was refering to is for oil pressure not oil temperature. Oil pressure should reach normal state within a few seconds of starting, ie, the oil light turn off. Oil temperature takes much longer to reach its normal operating state.

I think we already established that the noise is from ABS self-test.

sorry, missed 'pressure' thinking it was 'temperature'. I have the same noises as notdeafyet. Good to know I'm not the only one.

Re: throwout bearing rattle?
 

It's called gear-rollover noise, and it's normal. Miatas & RX7s had this as well, most Mazdas do. The reason it sounds loud is due to the engine being so damn quiet at idle.

what does it do?

the gear roll-over

anyway, so its no cause for alarm?
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