2004 Saab 9-3 Owner's Manual - Page 253

Car care 253 Anti-corrosion treatment The entire car undergoes a series of anticorrosion processes during production. These include electrophoretic priming, PVC-based coating to protect against stone chip damage and corrosion, and treatment of body cavities and members with thin, penetrating rustproofing oil. In addition, most body panels, such as the hood, doors and floor pan are galvanized. The anti-corrosion treatment on some parts of the car is constantly exposed to wear and prone to damage. This applies particularly to the underside of the car and inside the wheel arches, where grit, road salt and the like that are thrown up can give rise to corrosion where the underseal has worn away. The extent of this obviously depends on the conditions in which the car is used. Accordingly, make it a habit to hose the underside of the car often and to inspect the condition of the underseal. The anti-corrosion warranty does not relieve the car owner of the need to carry out normal maintenance to the rustproofing and to make good any damage. Use a hose to clean the underside of the car thoroughly. After it has dried, use a brush or spray to apply a viscous anti-corrosion agent to any worn or damaged areas, to prevent the onset of corrosion. Even after the anti-corrosion warranty has expired, it makes good sense to continue to maintain the rustproofing. Seams in the body, especially those in the doors and trunk lid, are particularly vulnerable to corrosion from the outside, caused by grit and salt thrown up from the road, and to corrosion from the inside, largely as a result of condensation. Keep the seams clean and at the first sign of any rust, apply a thin, penetrating, anti-corrosion oil. Your Saab dealer will be pleased to give you further advice. What causes rust? Steel body panels of automobiles are subject to rusting whenever air and moisture manage to penetrate the protective finish. Body panels may rust through if the process is unchecked. Rusting can occur wherever water is trapped or where the car's panels are continuously damp. Damage to paint and undercoating by stones, gravel and minor crashes immediately exposes metal to air and moisture. Road salts used for de-icing will collect on the bottom of the car and promote rusting. Areas of the country with high humidity have a greater potential for rust problems, especially where salt is used on roads or there is moist sea air. Industrial pollution (fallout) may also damage paint and promote rusting.