What's this noise? 4runner is off

[Sleeping-bear]

Hey all,
I took the dog out a minute ago and heard my 4runner humming. Sounded like a small air compressor running... This got my attention right away. It was coming from the rear end, in the area of the spare tire. But I couldn't pinpoint it for the spare being in the way.

I didn't want to waste time lowering spare in case it was causing damage.

I started the truck, no strange startup or sounds. Turned it off and noise was gone.

Drove it up the road, all seems ok.

I drove in town and back today, first snowfall. Nothing crazy.

Only mods on rear end are; breather kit on transfercase, e-locker. And understating a few months ago. Fluid film.

My rig is a 2016 t4r, trail. About 17,000 km on it.

Truck hasn't been running for a few hours before hearing the noise.

Here is a link to a short video of noise
https://youtu.be/vcDEB8MnrEs

Any feedback would be greatly appreciated. It's stressing me out...
Ps I'm clearly no mechanic, so bare with me if this is something normal... I've never had this happen on any vehicle that I've noticed in almost 25 years of driving.

 

[Sleeping-bear]

I did go through the automatic carwash yesterday. Temps are hovering around 0.
I sped through the under spray to prevent damage to my undercoating.

 

[nb rob]

From the manual:

"Approximately five hours after the engine is turned off, you may hear sound coming from under the vehicle for several minutes. This is the sound of a fuel evaporation leakage check, and it does not indicate a malfunction"

Also is in the stickies:

http://www.toyota-4runner.org/5th-gen-t4rs/63923-noise-comming-rear-my-4runner-limited.html

Totally normal

 

[GearJunkie88]

Hey all,
I took the dog out a minute ago and heard my 4runner humming. Sounded like a small air compressor running... This got my attention right away. It was coming from the rear end, in the area of the spare tire. But I couldn't pinpoint it for the spare being in the way.

I didn't want to waste time lowering spare in case it was causing damage.

I started the truck, no strange startup or sounds. Turned it off and noise was gone.

Drove it up the road, all seems ok.

I drove in town and back today, first snowfall. Nothing crazy.

Only mods on rear end are; breather kit on transfercase, e-locker. And understating a few months ago. Fluid film.

My rig is a 2016 t4r, trail. About 17,000 km on it.

Truck hasn't been running for a few hours before hearing the noise.

Here is a link to a short video of noise
https://youtu.be/vcDEB8MnrEs

Any feedback would be greatly appreciated. It's stressing me out...
Ps I'm clearly no mechanic, so bare with me if this is something normal... I've never had this happen on any vehicle that I've noticed in almost 25 years of driving.

Some sort of emission vacuum. Nothing to be worried about. First time I heard it, I googled it and found a page on this forum explaining it. http://www.toyota-4runner.org/5th-g...mming-rear-my-4runner-limited.html#post537031

 

[Sleeping-bear]

Awesome. Saved me from stressing!

Sorry for posting a thread for something already covered. Strange I never heard anything like this before. Can't recall my FJ ever doing it.

Thanks allot for the quick response.

Just got a sassy comment from the wife... "typical man, didn't read the manual"... lol

 

[nb rob]

Awesome. Saved me from stressing!

Sorry for posting a thread for something already covered. Strange I never heard anything like this before. Can't recall my FJ ever doing it.

Thanks allot for the quick response.

Just got a sassy comment from the wife... "typical man, didn't read the manual"... lol

No worries! Sunday nights are for relaxing

I was once puzzled by that sound too. Coming from a Nissan; any glance under the truck or any noise at all was stressful.

 

[Z-man]

I've had it stay on all night, definitely not right. It sounds like the fuel pump. Almost to 5k service and will check out.

Also notice HVAC fan is loud as well. Anyone have that?

 

[chris_1001]

Yup, a few days after getting my 4R, I heard the same hours after I got home. Kinda freaked me out. Started and stopped the 4R and it went away.

But got the same info that it was the emission system doing its thing. Whew!

 

[702_SR5]

I've had my new 2018 SR5 for nearly a month. Went out to the garage a few minutes ago and heard this noise. Wondered if I could find anything about it on the internet and sure enough, I found this thread! No, I haven't read the manual word for word yet! :biggrin1:

Only thing is, it has been more than 5 hours since I shut down the vehicle. In fact, it has been close to 8 hours. I'm the only one here, so no one else has turned the key or started it. I was in the garage maybe half an hour ago, and opened a side door to get something out of the vehicle, and the sound wasn't happening then. :wtf:

 

[Auntie Soshul]

There’s a description and explanation of the sound in the FAQs located in the stickies of this forum.