How to Protect the Underside of Your Audi 4000 from Corrosion
Keeping the underside of your Audi 4000 free from corrosion can help prolong the life of your car and prevent expensive underbody repairs. Newer cars can sometimes be purchased with underbody rustproofing already included; but for older cars, rustproofing needs to be re-applied at least once a year. Here are some useful tips on preventing corrosion damage on the underside of your Audi 4000. Note that these steps will work only on very small damaged areas; more extensive damage will require the work of professionals.
- If you drive your Audi 4000 on most days, wash it at least once a week -- both the body and the underside.
Road salt and grime accumulate easily on the underside of your car. By using an ordinary lawn sprinkler, you can wash away most of the salt and grime that have caked underneath your car. You can also use a pressure washer although it would take some time and effort to reach all the nooks and crannies without hoisting your car on a lift or a ramp. Also remove and wash the floor carpets at least once a month and more frequently during winter when road salt can be carried inside your car by your footwear.
- Aggressively inspect the underbody and repair any damage immediately.
After you wash your car and waited for it to dry thoroughly, drive it inside the garage and inspect the underbody and the wheel wells with a flash light and a large mirror attached to a long handle. Alternatively you can take your car to a garage with a lift, ramp, or axle stands and then check the underbody directly with the flashlight. You are looking for minute chips, pits, and scratches on the painted metal surfaces or where the underbody sealant has come off. If you see any exposed areas, use a fine grade of sandpaper (220 or finer) to clean out the damaged area itself and the area immediately around it. You might need to use coarser sandpaper on larger damaged areas. You might also need to wrap sandpaper onto a screw driver or use specialized brushes (with non-metal bristles) to clean the dirt and remove some of the paint and underbody sealant on these damaged areas. Afterwards you would need to clean the damaged areas with a clean rag and some rust remover. After the rust remover has dried (you might need to wash any excess off as well), you then can apply (in sequence and after adequate drying time) some rust inhibitor (or a primer), touch-up paint, and then a manufacturer-recommended underbody sealant. Applying paint and sealant on the underbody does not require as meticulous a care as touching up nicks on the body of your Audi 4000. You can use a set of 2-inch (50-mm) paintbrushes to apply all these compounds separately. Make sure that these compounds do not get onto any component of the braking, engine cooling, exhaust, hydraulic, powertrain, and suspension systems.
- Make sure to have the underbody treated professionally with an anti-rust treatment before winter sets in.
De-icing salt is more damaging than the sand and small pebbles that regularly get thrown up onto the underbody of your car. Dissolved salt gets inside the nooks and crannies of your car and is very good at accelerating corrosion. Unless you keep your car in garage hibernation throughout winter, it's a smart choice to invest in a good-quality anti-rust job done by professionals.