What to Do When Rust Spots Appear on the Car Roof?

[MacJune]

If the rust is not severe, you can first use very fine water sandpaper dipped in water to gently sand off the rust spots, completely clean the area, and then apply a layer of primer. You can purchase a touch-up paint pen in advance. After the applied primer has dried, sand it smooth with water sandpaper, and then use the touch-up paint pen for color treatment. Keep a tube of ordinary toothpaste in the car. If you notice small new scratches, apply a little toothpaste. Reapply after rain or car washing.

[McJade]

I've personally experienced the issue of roof rust. Last month while washing my car, I noticed two pinhead-sized rust spots on the roof. I didn't pay much attention at first, but within two weeks they had expanded to the size of coins. I immediately purchased a rust removal kit to address it: First, I carefully sanded the rusted areas with 800-grit sandpaper until the bare metal was exposed, making sure no rust remained. Then I applied a metal converter and let it react for 20 minutes—this step is crucial as it prevents further internal corrosion. After that, I applied two coats of epoxy primer and finally sprayed on the matching topcoat. However, color mismatch is inevitable with touch-ups, especially noticeable on my white car that's often parked outdoors in direct sunlight. Now I inspect the roof and drainage channels monthly, and if I find any scratches, I touch them up immediately. I also keep a rust remover pen in the car for emergencies. My advice: if rust spots exceed the size of a fingernail, seek professional panel beating immediately—otherwise, water leakage could become a serious issue.

[LeKayden]

A couple of days ago, my neighbor found rust spots on the roof of his SUV, and I happened to help him deal with it. Actually, roof rust usually starts from small points caused by bird droppings acid erosion or stone chips. The treatment process is quite simple: wear gloves, sand the rust spots clean with fine sandpaper, making sure the area is slightly larger than the rust spots. Apply anti-rust primer and let it dry naturally for half an hour, then finish with a touch-up pen. The key point is to choose a continuous sunny day for the work, as high air humidity can cause the paint to bubble. Also, never take shortcuts by spraying paint directly over rust spots, as the rust will spread from inside, causing the paint to bulge in chunks after a few months. Daily maintenance requires special attention: tree sap and bird droppings should be cleaned on the same day, and avoid using corrosive cleaners when washing the car. If you notice water seeping from the edges of the seals, address it promptly, as this is the root cause of rust.

[VanJustin]

The treatment for roof rust depends on its severity. For minor rust spots, you can handle it yourself with rust remover and a touch-up pen, but be meticulous: first use scratch wax to remove surface rust, then apply rust inhibitor in dots, and finally cover with paint. Note that touch-up paint should be applied in thin layers, with 15-minute intervals between each layer. For moderate rust, it's advisable to visit an auto repair shop for partial repainting, costing around 300-500 RMB. If the roof metal is rusted through, the entire section needs to be cut and replaced, which not only affects structural integrity but may also lead to leaks after repair. For prevention, applying hard wax to the roof every quarter is effective, especially paying attention to areas where water accumulates, like sunroof tracks and roof rack bases. In northern winters, promptly clear snow from the roof after snowfall, as de-icing salt can damage the paint. When parking outdoors, try to avoid spots under dripping air conditioner units.