steering makes groaning sound when turning

when i turn the steering wheel when idle or at lower speeds i get this groaning sort of sound.
what would it be?

 

Check your power steering fluid?

 

Lack of power steering fluid, check the reservoir.

 

^^^Check your fluid.

 

and if your fluid is low, you most likey have a leak. Ps fluid doesn't just go low on it's own.

 

yup it must be a leak...

 

There is also a screen at the bottom of the reservoir that gets dirty and plugged causing noise. (basically causes low PS fluid symptoms even if it isnt low) I sucked the reservoir empty and shop vacuumed the screen clean and havent had a problem since.
Some guys just jam a screwdriver through it and it fixes the problem too. Most vehicles dont have the screen there anyway