How Long Should Oxalic Acid Soak the Three-Way Catalytic Converter?
3 Answers
Oxalic acid soaking the three-way catalytic converter takes 30 minutes to 1 hour, ensuring all areas are evenly soaked to avoid uneven treatment. The three-way catalytic converter transforms harmful gases such as carbon monoxide and hydrocarbons emitted from vehicle exhaust into harmless gases through oxidation and reduction reactions. When high-temperature exhaust passes through the purification device, the catalyst in the three-way catalytic converter enhances the activity of harmful gases, promoting redox chemical reactions to purify the exhaust. Oxalic acid soaking can be used for rust removal, but caution is required. Oxalic acid has strong corrosiveness to stainless steel, and high-concentration oxalic acid can also corrode the skin. Additionally, the generated acid oxalate salts are highly soluble and somewhat toxic. If skin comes into contact with oxalic acid, rinse with water immediately.
I've been working in auto repair for nearly twenty years and have seen many car owners use oxalic acid to clean their catalytic converters. Generally speaking, soaking it for 20 to 30 minutes is the safest approach, but the exact time depends on the degree of clogging. Oxalic acid is acidic, and soaking for too long can corrode the internal ceramic structure—I've personally seen cases where an hour of soaking completely ruined the part. During the operation, the catalytic converter must be removed and soaked in an oxalic acid solution with a concentration no higher than about 5%. After soaking, rinse it thoroughly with clean water before reinstalling. There are risks involved, so non-professionals should avoid attempting this, as oxalic acid can easily burn the skin or produce harmful gases. For regular maintenance, periodic checks of the exhaust system and using high-quality fuel can help reduce clogging issues. Ultimately, I recommend taking your car to a professional repair shop—they have the right tools to handle it safely and effectively, saving you from costly repairs due to damage.
I've cleaned my car's catalytic converter myself before, and soaking it in oxalic acid seemed quite convenient. I tried soaking it for about 25 minutes, and the effect was good—most of the carbon deposits dissolved. The process is simple: first, remove the catalytic converter and soak it in the oxalic acid solution, keeping the concentration below 10%, as leaving it too long can cause issues. After soaking, rinse it thoroughly with plenty of water to avoid acidic residue damaging the car. But honestly, this method is controversial—some experts say oxalic acid can accelerate the aging of the catalytic converter's materials. While it worked for me, I wouldn’t recommend it to everyone. For safety, I wore gloves and goggles the whole time and worked in a well-ventilated area. Relatedly, there are many DIY tutorials online suggesting soaking times between 15 to 35 minutes, but I found the actual effect depends on the car’s condition—older cars might need a bit longer. In short, if you insist on doing it, keep the soaking time around 20 minutes, but pay close attention to how the car responds.
