One way to improve vehicle gas mileage, and thereby reduce greenhouse gas emissions, is to make the vehicle more lightweight by replacing the heavy steel components within the vehicle, such as the engine cradle, with magnesium, which has a similar strength-to-weight ratio but that is dramatically lighter. However, magnesium is easily corroded and not currently in use in exposed areas of the vehicle. Coating the magnesium with the polymer polyetherimide (PEI) can improve corrosion resistance, as PEI is hydrophobic, resistant to aqueous solutions and hydrocarbons, and heat tolerant. The research presented here will detail the reduction in corrosion using PEI coated over magnesium using one of three methods – solution casting, polymer development from the monomer, and 3-D printing over the magnesium. The various deposition methods will be compared to determine the most effective method to improve corrosion resistance and ultimately move to incorporate magnesium in exposed areas of vehicles.