Power Steering Problem

About a week ago the car sat outside in below 0F temps overnight. The next morning the powers steering made a mowning noise. The fluid level was fine so I went ahead and drove the vehicle. After about 10min of driving the noise went away. At first I thought this problem was simply due to the cold weather, but now it is occuring when sitting at 50F for extended periods of time. The fluid level has never gone down so there isn't a leak.

Any ideas? The mowning tells me the pump is cavitating, but I am not sure how air entered if there isn't leak.

About a week ago the car sat outside in below 0F temps overnight. The next morning the powers steering made a mowning noise. The fluid level was fine so I went ahead and drove the vehicle. After about 10min of driving the noise went away. At first I thought this problem was simply due to the cold weather, but now it is occuring when sitting at 50F for extended periods of time. The fluid level has never gone down so there isn't a leak.

Any ideas? The mowning tells me the pump is cavitating, but I am not sure how air entered if there isn't leak.
it could just be the belt how clean is the power steering fluid? you may want to pump it out and change it. but what kind of car and moter?

Your pump may be on the way out. If the noise goes away eventually, I wouldn't worry about it. Mine moans when first started in cold weather too until it warms up. Always has.