Underbody MaintenanceChemicals used for ice and snow removal anddust control can collect on the underbody. If theseare not removed, corrosion and rust can developon the underbody parts such as fuel lines,frame, floor pan, and exhaust system even thoughthey have corrosion protection.At least every spring, flush these materials fromthe underbody with plain water. Clean anyareas where mud and debris can collect. Dirtpacked in close areas of the frame shouldbe loosened before being flushed. Your dealer oran underbody car washing system can do thisfor you.Chemical Paint SpottingSome weather and atmospheric conditions cancreate a chemical fallout. Airborne pollutants canfall upon and attack painted surfaces on thevehicle. This damage can take two forms: blotchy,ring-shaped discolorations, and small, irregulardark spots etched into the paint surface.Although no defect in the paint job causes this, GMwill repair, at no charge to the owner, the surfacesof new vehicles damaged by this fallout conditionwithin 12 months or 12,000 miles (20 000 km) ofpurchase, whichever occurs first.443