Hissing noise

Hello, i have an 07 tundra and i hear a hissing noise coming from under the truck, towards the back. The truck has been off and parked for several hours. I didnt notice the noise earlier but i just noticed it right now. Anybody have or had similiar problem?

 

It's the evap/emissions system. It makes noise a few hours after it's off. Purge or something. Someone else can chime in with the technical name.

How long does it go for?

 

Okay, thank you. I just went back out there and the noise stopped. It wasnt long.

 

These are noisy trucks for sure.

 

Lol yes they are. I have an 08 and he makes all kinds of rattles. Is the evap emissions expensive to fix? And how much damage can it cause if it goes on like this?

 

Hissing noise? Sure you don't have a serpentine belt in there somewhere?

 

This is normal. It's supposed to do it. Newer toyotas do it as well.

 

So that hissing noise is normal? Ive never heard it before and we have 3 tundras. Even on our newer 2016 tundra. I read somethings online about bad performance if goes unfixed? Sorrt im new here guys lol