Protection of the underbody/hidden cavities of the body with anti-corrosion agents (BMW 5 Series E39)

The entire underbody has a polyvinyl chloride (PVC) coating. The front wheel arches, which are particularly susceptible to damage from stone impacts, are additionally protected from the inside by plastic lining. The hidden cavities of the BMW car body have a special hard coating or are filled with a so-called molding compound. The molding compound is introduced into the cavities and, when heated to approximately 180°C, adheres completely to the surfaces to be protected. In addition, individual body parts are made of galvanized sheet metal. Before the cold season and after washing the underbody, it is necessary to check the condition of the protective coating of the underbody. Damaged areas are cleaned and coated with a hard anti-corrosion agent.

At the base of the body in the area of rotation of the wheels, dust, clay and sand can be deposited. Removing the accumulated dirt, which in winter may also contain salt, is very important. Preservation of the engine compartment: to prevent corrosion of the front part of the car (for example, side parts, longitudinal beams and partitions) and the power unit, the engine compartment and the brake system, front axle and steering components located therein must be treated with a high-quality solid preservative. In all cases, this should be done, of course, after washing the engine.

Caution: Before washing the engine, which can be done, for example, using an ether-based cleaning agent and a steamer, it is necessary to cover the generator with a plastic bag.

(The website served as the basis for the text «BMWman»)