Hooting noise

[Morania]

So whenever I put the Yota to bed after a drive, I hear a hooting noise coming from under the hood. It's a quick noise that sounds like air escaping from a plastic seal. I figured it was a vacuum thingy under there with a sketchy seal.

Now that the weather is warming up some, I can hear the noise a little bit as the temperature rise during the day- the truck hasn't been even started yet.

It's kind of cool. I'm not worried about it, just curious.

 

[JohnMc]

It's part of the gas tank vapor recovery system. I used to think it was a valve being operated by the system, but once I heard it happening on my car while the battery was disconnected (installing a winch). So it's just a pressure build up in the system that eventually pushes its way through a valve in a mooing/farting/hooting sound.

Later model trucks have a little chamber built into the charcoal canister box under the hood, some people do mods on their earlier style boxes to add a small amount of volume to the hose - this is apparently enough to change the resonant qualities of the air flow and stop the flatulence.

https://www.yotatech.com/forums/f2/3rd-gen-4runner-evap-canister-buzz-286103/

 

[rkntoy]

Charcoal canister - no biggie.

Have not heard it called "hooting" before

 

[Morania]

Oh, I love it. Just wanted to be able to explain it.

We're nearly at Hooter for the truck's nickname.

 

[Kanoe]

It's also commonly called the Moo Box.

 

[papapoopski]

Previous owner probably installed an owl to avoid winding up like this guy...http://www.toyota-4runner.org/3rd-gen-t4rs/253282-possible.html