Can you put too much refrigerant in an AC?

Yes, overcharging an air conditioning system by putting too much refrigerant into the closed loop is a common and highly damaging mistake that severely impairs cooling performance. When an AC system has an excessive charge of refrigerant, liquid backup occurs in the condenser and evaporator coils, causing operating head pressures to spike dramatically. This extreme pressure places intense mechanical strain on the compressor motor, causing it to overheat, trip internal thermal overloads, or suffer catastrophic mechanical failure known as liquid slugging. Symptoms of an overcharged system include warm air blowing from vents, clicking compressor clutches, and high electrical current draw. You can troubleshoot by checking system pressures with a manifold gauge set. You can verify correction when recovering excess refrigerant restores normal operating pressures and cold air output.