Saab 2007 owner manual Anti-corrosion treatment, What causes rust?, Preventive maintenance

Car care and technical information 245

Anti-corrosion treatment

The entire car is corrosion-protected at the factory in different stages by an electrolytic immersion coating and a PVC-based pro- tective coating to protect against corrosion caused by stones flung up by the wheels. A thin penetrating anti-rust oil is also applied in cavities and body members.

In addition to conventional anti-corrosion treatment like painting, underbody treat- ment and cavity treatment, most of the body panel surfaces are galvanized. These include the hood, the doors and the under- body.

The anti-corrosion treatment on the under- side of the car and inside the wheel arches is particularly exposed to constant wear and possible damage, the degree of which will obviously depend on driving conditions.

What causes rust?

Steel body panels of automobiles are sub- ject to rusting whenever air and moisture manage to penetrate the protective finish, and body panels may rust through if the pro- cess is unchecked. Rusting can occur wher- ever 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 coun- try with high humidity have great 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.

Preventive maintenance

The following procedures are necessary to help protect against rusting. Refer also to the terms and conditions of the Sheet Metal Coverage described in the warranty book- let.

1Wash the car frequently, and wax at least twice a year. Under adverse con- ditions, where there is a rapid buildup of dirt, sand or road salt, wash your car at least once a week. After extreme expo- sure to salted snow or slush, evidenced by a white film on the car, wash the car immediately. Frequent washing will pre- vent paint damage from acid rain and other airborne contaminants such as tree sap and bird droppings. If any of these contaminants are noticed on the car the finish should be washed immedi- ately.

•Begin washing by rinsing the entire car with water to loosen and flush off heavy concentrations of dirt (include the underbody).

•Sponge the car with a solution of either a good quality car soap or mild general purpose (dish washing) detergent and water.

•Rinse car thoroughly with clean water.

•After washing, check and clear all drains in doors and body panels.

•Wipe the car dry, preferably using a chamois.