I've had a constant sound coming from my '08 Prius for a couple months now that sounds like an outboard boat motor. As the vehicle picks up speed the sound increases in pitch. If I'm coasting and foot is off the gas, the sound is still present but goes down in pitch. Even when I think the car is running on the battery I can hear the sound. I had a tech at the dealership take a long look at the engine and he didn't find anything wrong. We did hit a chunk of ice a few months back that sounded rough on the undercarriage. However, I'm not sure that coincides with when the sound started. Now that the winter from hell is over, I managed to crawl under the vehicle to look at the exhaust system and didn't see anything. Does anyone have any thoughts on what it might be?
Common to lose a front wheel bearing on a G2. Find a nice quiet stretch of road or big empty parking lot where you can swerve around a little and as you turn the steering wheel see if that sound changes. if you turn left and the sound gets worse its the right wheel bearing If turning right and the sound gets worse its the left wheel bearing. No change in sound its probably not the wheel bearing. Mine front drivers wb made a wuup wuup sound that started at 20 miles an hour and got worse with speed.
Thank you! The sound seems to get louder when swerving left and softer when swerving right. Must be the right wheel bearing then. Would it be recommended to do the left wheel bearing as well since they're on the same axle, or does that not matter? I plan on ordering the parts myself and having a local repair guy do the install and I'd like to do OEM parts. Does anyone know the part numbers off hand or if I need to order more then just the bearing?
Yes sounds like the right. No just do the one. I lost my drivers side and 10 years later no other wheel bearing. Theirs lots of posts about wheel bearing installs on this site one may have the part number. Use the "search forums" button up top. Good luck.
We have had a few cases where the exhaust manifold that connects the engine to the exhaust pipe has rusted out, presumably from winter road salt. https://attachments.priuschat.com/attachment-files/2016/02/101575_CAM00045.jpg https://priuschat.com/posts/2310242/
Could also be tire noise. Swap tires from left to right and see if it now switches sides when swerving.
But then it would stop when you let off the gas and combustion stops completely. Even above 43 MPH where the engine still has to spin, the intake valves are wide open and there is no exhaust.
Just wanted to send an update that we did have the front right wheeling bearing replaced and the sound is gone now. Thank you for the help!
