Diagnosis
Excessive noise is usually a sign of an airflow obstruction or a loose component vibrating, not a defect in the compressor or fan motor itself.
How to Fix It
First, ensure both exhaust hoses are fully straight and not collapsed or bent sharply. A restricted hose forces the fan to work harder. Second, check that the air filter behind the front grille is clean and seated properly. A clogged filter strains the system.
If That Didn't Work
The noise could be the plastic housing vibrating against the window bracket. Try adjusting the tension on the window slider or placing a folded towel between the unit's case and the window frame to dampen vibrations.
Heads Up
The "Turbo" or "High Cool" setting will always be significantly louder. For sleeping, use the regular Cool mode or the Sleep setting, which automatically lowers fan speed.