Weird noise on freeway

Road and tire noise is very common with the Prius. The Prius is a quiet car, but not well insulated. On a smooth road it is inherently quiet, but on a rough road the sound easily penetrates the cabin. Our OEM crappy tires made a lot of noise. When we switched to Micheline MXV4+ Energy tires the ride quieted down a lot. Try driving on a different road and see if the sound changes.

Tom

 

Strange noises make me looney to. I hear things no one else seems to.
Here's what I would do. Try to get it down to either drivetrain or chassis noise. Get up to highway speed where you can hear it. Slap the trans shifter into neutral and coast a while. Try windows open too. If you can't hear it in neutral it's probably motor. Might be the inverter whining. If you still hear it in neutral its chassis/tire noise.Slow down then and see if the sound changes with speed which would indicate tires.If tires check for proper inflation 44frt/40rear or maybe something stuck in tire treads.
If you think its motor noise there's a post around here that has directions to get ICE/motor on in park to test it. Series of button pushes. Search. In Park with motor on you can pull the air cleaner off a little to get to the electric motor that controls the t.b. butterfly. Pull the electric plug off the throttle body which controls that motor and you can then control the throttle body butterfly by hand to rev up the motor.Hows the oil?
Oh and my 07 is really quiet.Just tire/road noise.

 

The loudest noise on mine, is the AC fan speed before it reaches the desired temp on auto.

 

One other possibility is a wind whistle from the screw holes on the bottom side of the outside mirrors. Try putting some black electrical tape over them if they're open and see if that does anything.

 

The mirrors can make weird sounds on the highway.

 

I too have the "road" noise on certain types of pavement. I am glad to see that it appears to be normal.

 

talk about funny noises cars make. i had one of these bad boys many moons ago. see those sidepipes? you should have heard the whistle they made!!

i cringe when i think of the gas mileage that thing got. it was a 1970 aar cuda. 340 6-pack (for those who dont know what that is, it had 3 2-barrel holley carbureturs.) it got 7 mpg in the city and 12 on the highway. LOL. man those were the good ole days!!

 

Will insulating auto; will undercoating cut down on road noise??

 

Not the expert but I doubt undercoating will help that. You'd have to go after deadening panels everywhere, I would think, plus the tire itself.

 

Better tires help a lot. Get rid of the OEM tires and put on some real rubber.

Tom