engine turned off for about 30 mins...this is the 3rd or 4th time I hear this.
2016 gs350 fsport awd

 

Sounds like a dying cricket or something... does that help?

Very odd though, especially after the engine has been off for about 30 min as you said.

 

That's an odd sound. With mine, I hear a faint squeaking noise after I turn off my engine for about 3-5 secs. I traced the noise and it seems to be coming from the radiator fans as they're coming to a stop. Don't know how u can lubricate that. But u can only hear it in a fairly quiet environment though, like inside a garage. Does ur GS do that too??

 

Might be emissions equipment doing its thing...

 

My cousins a tech at Toyota and I just got back from the Lexus dealer....showed them the clip as it wasn't making that sound at the dealer.
Cuz and other tech say its the purging valve....its purging vapour from fuel or something like that...so yes its to do with emissions.
LOL, the tech at the dealer says "if you don't see any warning lights, you got nothing to worry about"

 

This car makes some interesting noises then.

 

Lol...true! It does make some interesting noises....not as many noises as the BMW I had previous to this car.

heres my contribution to the wonderful pics I've been seeing of the GS350's

 

I've heard that in my 2014 glad its normal