Sucking air after ignition turned off

[Liberty 1]

Hi,
I have an issue when i turn my ignition off there is a sucking sound from the air box that lasts for a couple
of seconds post ignition turned off.

took air box off and noise is coming from the flex pipe leading to the airbox

Anyone that could suggest possible causes , i would appreciate the feedback as i haven't had this before.

[Dr HaxZaw]

The only thing i can think of is the bleed from the block to the throttlebody to get rid of crank case pressure... other than that i dont have a clue

[Not_An_Abba_Fan]

Entirely normal. As the ignition is switched off, there is no more bang, but the pistons still move due to inertia and create low pressure in the cylinders momentarily. It is the air rushing in that causes the noise. Nothing to worry about.

[Liberty 1]

Only problem is that the noise wasn't there prior to a couple of days ago and now it is noticible from inside the car

[Not_An_Abba_Fan]

Have you changed the air filter recently?

[Liberty 1]

No the filter has been there for a while.

when i lifted the airbox lid the noise is somewhere from the throttlebody region back
it almost sounds like a vacume leak.

[Not_An_Abba_Fan]

Could be the PCV solenoid at the back of the inlet manifold. Check the hose on the bottom of your throttle body.

[Liberty 1]

Hoses are ok may have to take to mechanics as nobody has heard this noise before
Thanks