Airflow- driving

those would be the shutters right behind the grille. they close to help warm the radiator, and open to cool it.
do you have an owners manual? not sure what you mean by 'sounds llike sucking air', are you having a specific problem?

 

good morning. yes i did, any questions?

 

I remember a recent post about road grit getting into the parts of the shutter system that are supposed to rotate and binding it up. I would think that if the ICE was cold and the shutters closed there wouldn't be any commands to the radiator fans to operate. But when the ICE is at operating temperature and the shutters are stuck closed and maybe the ICE gets close to overheating and the radiator fans accelerate in an attempt to cool things off. That might make a sound. I haven't fully explored my shutter system yet to see if it freely rotates or is operated by a stepper motor. Don't try to force shutters open or closed. OP might do some checks with cold Prius made ready. You should observe shutters closed, and warm Prius shutters open. In Prius history there was a time when folks were manually blocking the radiator grill with foam grout backing.

 

If the grill shutters were stuck, they would not make a "sucking" sound. They would trigger a trouble code which would turn on a light on your dash. I can't begin to guess what that sound sounds like, so I can't help there other than to say it's not the grill shutters.

Are you sure it isn't just the tires or the different aerodynamics? Try riding in another Gen 4.

 

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