Knocking noise as car is turning off

desertmike680

Member
:
06 MazdaSpeed 6
When turing off the car, a knocking/clunking noise is present as the engine slows down and stops. Any insight to this? I'm not even bothering taking it to Mazda. Its always "cannot duplicate issue".
 
Really. Thats interesting. I'm tired of hearing it. I take extremely good care of my car, so I'm completely unsure.
 
You're not talking about the clicking and whirring you hear from the throttle body for about 5 sec or so when the car is turned off are you?
 
No not that. I had a mazda tech explain to me what that noise is. This noise appears as the engine is slowing down to a stop, not after its completely stopped. It typically dies down when the car reaches a normal operating temp. Turning off the car when its cold, sounds like the engine is going to drop to the street. But it drives fine.
 
Last edited:
First post after lurking here - but I actually have the same problem in my '06. When you turn off the car cold you can feel the engine move (only way to really describe it). I don't know if this could be a motor mount issue, but it drives and shifts just fine.
 
my car does what you discribe, more or less, even after its all warmed up. Pretty much everytime shutting it off, you feel and hear the engine seem to become unbalanced. Sounds similar to a plane propeller stopping (but obviously not as dramatic). Never thought too much into it, a few ms3's that i test drove did a similar shutdown.
 
I'm wondering if it's something to do with the engine being in the 3rd phase (power) and reaching ignition just as your turning off the motor?
 
Ok, everyone else seems to know what I'm talking about. I'm not sure why you dont. Its pretty damn obvious.

Hi,

I realize this is an old post but I have this problem too. It seems its common on the mazda 3's. Mine too is serviced regularly and looked after. It almost sounds like a rod knocking noise. Do you or anyone else have any idea about this problem?

Thanks
 
It's called "dieseling" by us old timers. Back in the day it could be caused by the timing being a little too advanced, engine too hot, bad fuel, fuel octane too low. Lower octane gas burns faster than higher octane which can cause compression ignition.
 
Back