Multiple sources identify specific model years of several Nissan vehicles as having significant reliability issues, making them risky purchases on the used market. Recurring themes across these sources include widespread problems with Nissan's Continuous Variable Transmissions (CVTs) and, for certain older models, a critical flaw in the cooling system that leads to transmission failure. Other notable issues involve faulty engines, electrical components, and structural integrity. Potential buyers of used Nissans are strongly advised to research specific model years and consider pre-purchase inspections to avoid costly repairs.