My 2001 model is making a loud noise!

I have almost 150K miles on my 2001 Prius. I have noticed that starting about 2 weeks ago the car makes a really loud whining noise when I accelerate. It gets loudest when I am traveling at 47-49 mph and then becomes a bit quieter at higher speeds. It seems to be coming from the engine. I had the oil changed and the emissions/safety test done last week. It is still as loud as ever.

Any ideas about what could be causing this noise? :blink:

Thanks!

Get them to check the wheel bearings.. I had to replace one of my wheel bearings on my 2001 just after 200,000 km, which IMO is pretty darned good for a component subject to wear and load.. That's the *only* major repair that the car has had, if you don't count the rear bumper structure and cover due to some guy rear-ending me..

a few quick questions and then some things to check.
1)does it do it when the car is stopped and the gear lever in B?
2)does it do it when cold and the car is running?
3)does it do it more when turning corners?
4)does the noise change when decelerating and accelerating?

if (1) is yes get yourself a 3 foot long piece of garden hose and start listening under the hood it should only take a minute to locate the cause of the noise. I recommend your neighbours garden hose.
if (2) suspect the vacuum motor for the valve on the front Cat for the hydocarbon absorber, it's a know problem
if (3) probably a CV joint
if (4) probably a wheel bearing

if you want to post a sound file we can give it a listen and make a quess.

[4)does the noise change when decelerating and accelerating?

if (4) probably a wheel bearing




Sorry it took me so long to get back-I was out of town (although not driving my Prius!) The problem is the wheel bearing! Now the part is on order and I will get it fixed on Tuesday. It is our only car so we will just have to take it easy 'til then....

Thanks

I have a loud noise on my 2002 Prius. It happens when I drive straight or make a left turn, but is silent when I make a right turn. Any ideas as to what it might be?

A wheel bearing failure is a reasonable guess. I suggest that you visit your Toyota dealer soon for inspection and diagnosis as this can be a serious safety issue.