As the power steering fluid in your car's power steering system breaks down it causes more wear and tear on the components. The fluid becomes less efficient at staying cool and doing its job, which is to provide hydraulic pressure to assist you in steering your car. Bad fluid can cause premature failure of your power steering pump, which in most vehicles runs at least a couple hundred dollars. If the pump should fail while you are driving it could be a serious safety concern. Pay attention to any steering sounds, jumpy power steering or stiffness.