cruZin163

Does anybody else noticed a Rattling Sound when you turn off ignition... The dealer said that is normal... Anybody have a second opinion?

Sean

any chance it is engine knock? do you use low octane fuel (below 91) ?

MR_X

iTrader: (5)

I use California's finest 91 octane and I get it too. Noticed it this morning. But the engine shakes a little bit too.

06r33z

iTrader: (2)

they told me thats normal, i have that same noise

QuicksilverZ33

iTrader: (34)

I have the same noise...I think it is the transmission comeing to a stop because when I hold the clutch in and turn the car off...the noise is gone.....

97supratt

iTrader: (61)

I have the same crappy noise. When the motor gets to a low enough rpm it shakes a bit more and you hear parts making noise. Usually its the engine and transmission.

Changvi

iTrader: (66)

Its normal. Don't sweat it.

DavesZ#3

iTrader: (26)

Yeap, clutch out in neutral and turn off the engine and it sounds like a bunch of rocks rolling around under the car. It's "normal", even brand new Zs on the lot do it.

97supratt

iTrader: (61)

I always press down on the clutch when turning off my z, it just doesn't sound right when its depressed. lol

eat rice z33

iTrader: (11)

got the same noise. kinda funny i dont mind it hehe

ZSpectrum

iTrader: (4)

just push the clutch in and you wont hear it

350ztoronto

iTrader: (10)

normal sounds like ur clutch is gonna fall off but its normal...

Kevins350z

iTrader: (36)

+1

bleufiend

iTrader: (4)

<<<Nissan Tech.

Thank nissan for a subpar throwout bearing design. Thats what causes the stones rattling sound when shutting off the engine. Also is what causes the stone grinding sound when the clutch is released and the cars in neutral.

roast

iTrader: (2)

Question: Do you even know what a throwout bearing is?

bleufiend

iTrader: (4)

Yes and if you understood the operation of it you wouldnt of asked that question.

Its a combination of the throwout bearing/friction disc/pressure plate assembly developing just enough play between each other to cause the rattling. Mostly though its the throwout bearing.

mistermojorizin

try turning off the engine with the clutch pressed down. no rattle.

roast

iTrader: (2)

au contraire...

The throwout bearing is what allows the pressure plate to freewheel when the clutch pedal is depressed. This is why your owners manual states not to leave the clutch depressed for extended periods of time. It puts unnecessary wear on the throwout bearing; they are only designed for intermittent use. Although when one starts to go bad, you really only notice it when the clutch is depressed.

The throwout bearing is not even loaded in that situation. When the clutch is released/engaged the pressure plate is no longer freewheeling thus the bearing is stationary and does not rotate with the pressure plate. The phenomenon you're referring to has to do with the transmission being connected to the idling engine. Even though the tranny is in neutral, since the clutch is engaged, the inner workings of the tranny still have to spin with the engine. Push the clutch in and the noise slows to a halt (the tranny gradually stops spinning). Same concept when you turn the car off in this situation and you get a rattle... it's because the tranny is being brought to a halt with the engine. Push the clutch in to disconnect the tranny from the engine.... no rattle.

Do I clearly not understand the situation?

MR_X

iTrader: (5)

actually I don't think is the tranny at all. Today I took the exhaust off the car and I had to move the car in the middle of this. I notice that the rattle wasn't there at all without the "y-pipe" back. Unless I have a different rattle.

QuicksilverZ33

iTrader: (34)

Mayby the exhaust was too loud for you to hear it...