What Causes Paint Bubbling on the Hood?
3 Answers
Paint bubbling on the hood can be caused by: Poor paint quality: This issue often occurs at roadside shops, which typically offer paint jobs at very low prices and use low-quality paint. Unprofessional construction conditions and processes: Painting requires strict conditions and high technical standards. The surface must be completely free of moisture before painting; the filler (putty) applied during the initial surface preparation must be thoroughly dried in a dry environment before entering the paint booth; the air hose connected to the spray gun must remain dry, with no moisture allowed. These factors are significant causes of paint bubbling on cars. Excessive paint thickness: Lack of attention during the painting process or limited technician skills can often result in overly thick paint application, leading to paint sagging.
Paint bubbling on the hood is mostly caused by rust and corrosion on the metal surface. Moisture or dampness seeps beneath the paint layer, forming bubbles—such as when water isn’t fully dried after washing or prolonged parking in rainy conditions. In high-temperature environments, metal expansion and contraction accelerate paint separation, especially common in summer or under intense sun exposure. Improper painting processes, like uncleaned underlying layers or the use of low-quality paint, can also lead to gaps and bubbling. Over time, untreated bubbles will expand and rust, affecting the hood's structure. I always recommend first checking the rust severity, sanding off loose sections, applying anti-rust primer, and repainting—or visiting a professional shop for a thorough repair to prevent minor issues from escalating.
I find the bubbling of the hood paint quite annoying, as rust usually hides beneath the bubbles. Last time I left my car by the seaside for a few days, the salt corrosion was so severe that bubbles appeared. Additionally, when stones chip the paint, moisture can seep in and cause bubbling. Improper car washing or parking under trees where bird droppings contaminate the surface is another cause. If left untreated, the bubbling can spread and corrode the entire area. I took my car to the repair shop, and the technician suggested using professional rust remover followed by a fresh coat of paint. However, he emphasized that regular cleaning of the hood and avoiding prolonged exposure to damp environments are more important to prevent future issues.
