Mystery noise when parked

[Licorice]

I was in the garage last night, my car hadn't been driven for about 4 hours; I heard a noise come from the back end ... it's a little difficult to describe, but it wasn't metallic like something clunking or knocking; it lasted about a second, and definitely sounded 'motorized', almost hydraulic if that makes sense. I heard it again about an hour later. I've heard it before, but only when the garage door was up, so I wasn't sure if it came from the car. But last night, the garage door was down and I heard it very clearly both times - definitely from the car, and definitely from the rear. Does anyone know what it could be???

 

[RedCal]

Did you have the keys with you? could be the fuel pump being primed (my ex's VW did it when you opened the driver's door)

 

[Kimberly Lazarski]

I second the fuel pump; many late-model cars periodically run the fuel pump and test for pressure drop to verify the fuel system-side emission controls are working properly. That may explain what you're observing in the Stinger. If there are any Kia techs who can verify or discredit this idea, maybe they could chime in?

 

[Licorice]

No, the keys were in the house. Having said that, they're just inside the door, so maybe they're always within range for that?? I should lock it (it's never locked inside the garage) and see if the spot where I keep the keys is close enough to trigger the mirrors/puddle lights?

 

[jthrelf]

Third the fuel pump. My WRX manual even made mention that it was normal and happens about 8 hours after shutoff.

 

[Licorice]

I don't think the keys are triggering anything, but from these fuel pump suggestions, sounds like it's independent to the keys being in range anyway? Have you guys ever noticed the noise yourselves?

 

[ThunderBoy724]

I also agree on the fuel pump noises. My wife's Corolla used to do this for hours after being driven Makes whirring and hissing noises. You wouldn't notice it outside with ambient noises but inside a quiet garage it is more noticeable. It's just the fuel system and emission controls doing some kind of regeneration something or other. It's got nothing to do with the key being close to the car. Nothing to worry about. Nothing wrong with the car.

 

[Licorice]

Cool ... thanks everyone for suggesting what it likely is. I wasn't 'worried' about it as much as curious about what it might be. Mystery (probably) solved!!

 

[vipeboy2000]

yep, most cars do this with the evap system 5-8 hours after shut off it seems.. Why is my Toyota making a noise at the back near the fuel tank with the engine off?

there seems to be a thread about this on pretty much every brand forum lol.. quick google shows toyota, subaru, honda and gm right at the top.

 

[NS_Stinger]

This noise is caused by the vacuum pump inside the fuel evaporation leakage check module (ELCM). Depending on conditions, the pump will come on for about 15 minutes about 5 to 10 hours after engine shutoff. Both my Stinger and CRV do it.