High pitch sound from air intake when engine shuts off

S

Swayne

Member

:

CX5

• Jul 25, 2012

• #1

Hi all

new to fourm, new mazda owner.
Notice on CX5 in garage when I shut off engine, heard a low volume but high pitched sound. Open hood started and stoped engine, sound was comming from small box on lower air intake hose. Sound lasted for about 20 to 30 seconds, then an audible click sound (relay?). Happens every time.

Anyone know if this is normal? Thanks

 

S

stromdriver

:

Mazda CX-5 Touring w/bose-tech

• Jul 25, 2012

• #2

yeah its normal, it was covered previously on this forum, not sure where the thread was

 

C

CX-SV

Member

Contributor

:

2013 CX-5 GT AWD w/tech (Mar'12-Jul'14)

• Aug 2, 2012

• #3

Yes normal, anybody know what causes it?

 

N

njaremka

Wiggity-Wack-O-Tack

Contributor

:

2012 Mini R55

• Aug 2, 2012

• #4

just about every car does this. most have the sound muffled by the intake tubes.

when you turn the engine off, at least one of the cylinders will have some amount of compression pressure left inside it. the sound is the pressure release.

 

I

IHeartGroceries

:

Mazdaspeed6

• Aug 2, 2012

• #5

Sounds indicative of the servo motor in the throttle body performing a cycle once the engine is shut off. I believe most Mazda's do this. Or, since they have used drive by wire anyway...

There is also the possibility of a hissing from evap system functions, or the cooling fan staying on for a time after engine shutoff, if ECT is above a pre-determined threshold.

 

Y

youzi

Member

:

2013 Mazda CX-5 GT AWD

• Aug 19, 2012

• #6

i somehow think it is something electrical, not mechanical. Because it also makes that high pitch sound when u not only when you turn on and off the car, but also when you just turn on and off the accessories. Always wondered what it was as well.......

 

C

CX-SV

Member

Contributor

:

2013 CX-5 GT AWD w/tech (Mar'12-Jul'14)

• Nov 12, 2012

• #7

Sounds electrical, what is it?