1. Low Power Steering Fluid: Check the power steering fluid level. If it's low, top it off with the recommended type of fluid and bleed the system to remove any air pockets.
2. Damaged or Worn Power Steering Pump: If the pump itself is damaged or worn out, it can cause a loud noise. Look for any visible damage or leaks and check the condition of the pump's belt.
3. Air in the Power Steering System: Air in the system can also create noise. Try bleeding the system again and ensure there are no leaks in the hoses or connections.
4. Faulty Power Steering Rack or Linkage: If the steering rack or linkage is damaged, it can also cause a loud noise when turning. Inspect these components for any signs of damage or wear.
5. Lack of Lubrication: Ensure that all the necessary lubrication points on the power steering system are properly lubricated.
If you're not comfortable inspecting and repairing these components yourself, it's best to take your vehicle to a qualified mechanic for further diagnosis and repairs.