In general, rust is more likely to occur in areas where there is a lot of moisture and salt, such as coastal regions or areas that experience heavy snowfall. In addition, vehicles that are not regularly washed and waxed are more susceptible to rust, as the salt and other contaminants can accumulate and eat away at the paint and protective coating of the vehicle.
If the frame of a vehicle has major rust, it can compromise the structural integrity of the vehicle and make it unsafe to drive. In these cases, it is typically recommended to replace the frame or take other steps to repair the damage.
As for whether or not it is "normal" for a 2001 Kia Optima to have major rust, it is difficult to say definitively. It would depend on the specific vehicle and its history. However, if you are considering purchasing a used Kia Optima, it would be a good idea to have it inspected by a qualified mechanic to assess the extent of any rust and to make sure that the vehicle is safe to drive.
