NHTSA Service Bulletin 11003649: 2000-2024 Scion 4runner

The condition known as acid rain is caused by airborne chemicals or particles in the atmosphere, which mix with rainwater, nighttime dew, or high humidity to form acidic compounds. If these contaminants settle and remain on a painted vehicle surface, especially the horizonal areas of the hood, roof, and decklid, significant damage can occur. This damage is the result of actual etching of the paint and appears as pitting or water spots. As acid rain droplets on the vehicle surface evaporate, the concentration strength of the acid increases, causing deeper and more rapid damage. This evaporation and corrosive action also occur more rapidly on dark colored cars as direct sun heat increases. While Toyota paint quality, durability, and resistance to environmental factors is continuously being improved, it remains the responsibility of the dealer to protect and maintain the vehicles paint finish from the time of arrival at the dealership until retail delivery to the customer. In areas known for high frequency and/or concentration of acid rain (see Figure 1), frequent vehicle washing during high heat or humidity periods will minimize the potential for paint damage caused by acid rain. It is further recommended that either reverse osmosis or deionized water be used to prevent water spotting.