Humming after stopping and engine turned off

[Ashino12]

Hello,
This is probalby posted before but I can't find a similar post. As background I'm a non tech person. I have a 2018 Nissan Navara STX, done 75,000k's. Currently doing a camping trip around Australia and have just noticed that the engine quietly hums for about 10 seconds every 30 minutes after I've switched the engine off. This goes on for several hours. Now this is slightly annoying to campers. I disconnected the battery but it still happens. I did read on Google that a pump runs for a while to cool the turbo to make it last longer. But why would it run if the bettery is disconnected. If its needed can the interval be shortened or if its not needed can a service centre disconnect it.

 

[landmannnn]

Certainly the egr cooler runs for a little while after shutdown.
I don't think that is what you are describing though.

 

[Ashino12]

Certainly the egr cooler runs for a little while after shutdown.
I don't think that is what you are describing though.

Thanks for your thought, I'll call my service centre and see what they say.

 

[MANNING]

do you have a rust prevention unit on the car?

 

[landmannnn]

The other possibility is a GPS tracker. (Basically a simple mobile phone which can make your speakers buzz)

 

[Ashino12]

The other possibility is a GPS tracker. (Basically a simple mobile phone which can make your speakers buzz)

No rust prevention unit that I'm aware of. The noise is coming from sort of under the engine bay not from inside. Its very consistant on the hour. I'm wondering if its heat related. It sounds like a motor running. I'm off to see a local dealership. Thanks again for your thoughts.

 

[MANNING]

( dont quote me) mine humms aswell..
I originally thought the rust prevention dooka, but possibly fuel being pumped (so fuel pump humm) up or down to keep or relieve pressure?

 

[Ashino12]

( dont quote me) mine humms aswell..
I originally thought the rust prevention dooka, but possibly fuel being pumped (so fuel pump humm) up or down to keep or relieve pressure?

OK a friend of a friend who is into Navara's said the same. When the fuel tank empties or gets low the air pressure does not equalise in the tank and a pump is trying to stabalize the air pressure. He said to just unscrew the filler cap. Going to try that tonight.

 

[MANNING]

...He said to just unscrew the filler cap...

That friend of a friend may indeed be right.. If it is indeed the same humm we have, mine has been doing it since i bought the car new in 2014 and there isnt any negative actions because of it

 

[Ashino12]

Looks like the friend was correct. Returned from a day trip. It started a few minutes later. Released the fuel cap and didn't happen again. Booked a service in two weeks so will see what they say. Hope others will benifit from this thread. And thanks Manning for contributing.

 

[NavaraNavara]

Interesting