If the oil in the steering reservoir tank is bubbling.
Check that the oil level in the steering reservoir tank is between MAX and MIN.

Due to steering oil leakage and lack of oil, there is not enough oil in the internal parts of the oil pump, which causes parts to damage each other, causing abnormal noises when you turn the steering wheel.

If the noise is loud, replace the steering pump and repair the area that is causing the oil leak.

If you continue to ignore the abnormal noise, in the worst case scenario, metal powder generated by parts damaging each other inside the oil pump will enter the steering rack, etc., and the steering rack and steering hose will need to be replaced.

If you notice the oil in the steering reservoir tank bubbling before you heard the strange noise, look for the oil leak.
Or, as an emergency measure, replenish the reservoir tank with the appropriate amount of steering oil.