I have a 2008 Prius with 111,000 miles on it and lately, I hear a loud chirping, whining sound that is louder under acceleration and seems to vary only according to acceleration or deceleration. Acceleration makes a louder sound. The noise does not occur when vehicle is cold and first driven. It's only after it's driven for awhile and things are warmed up but then again, it doesn't always do it even though it's warmed up. Not sure I could reproduce the sound if I brought it to a dealer for service. When the noise does start up, it's very apparent and loud and then, after awhile, it goes away temporarily only to start up again. What do you guys think?
Hi. I have a 2007 with the same symptoms you mentioned. I didn't see any reply to your question. I was going to ask the forum the same question but I thought I'd ask you first if you've been able to figure out what is causing the whining sound? Thanks.
The first guess on this sort of thing is wheel bearing. Try turning left and right sharply and see if the sound is different as a result of different loading on the bearings.
You also may want to check your brake pads. The pads have wear indicators and they give off a chirping sound.
Second it does this put the car in neutral and see if the sound goes away. If so its engine related not running gear. Try putting the car in inspection mode and listen under the hood. Also given your mileage your way over due for many maintenance items. Sometime addressing those will reveal issues. Like going to the doctor for a check up. 1---Trans fluid replacement 2--Both engine and hybrid coolant replacement
