What is the impact of oxalic acid on the three-way catalyst?
2 Answers
Oxalic acid may weaken the purification effect of the three-way catalyst, leading to issues such as increased emission pollution, primarily due to improper cleaning. The oxalic acid solution should be mixed with water at a ratio of 1:10; otherwise, it may damage the three-way catalyst. Steps for cleaning the three-way catalyst with oxalic acid: 1. First, use a lift to raise the vehicle and completely remove the three-way catalyst. 2. Soak and clean the three-way catalyst with the oxalic acid solution, then rinse it with clean water. 3. Reinstall the cleaned three-way catalyst into the vehicle and start the engine for testing.
I've been repairing cars for over 10 years and have encountered many cases where car owners used oxalic acid to clean their catalytic converters, all with disastrous results. The strong acidity of oxalic acid directly corrodes the precious metal coatings inside the converter, such as platinum and palladium. Once these catalyst coatings are corroded, the conversion efficiency plummets. The catalytic converter's primary function is to reduce emissions of carbon monoxide, hydrocarbons, and nitrogen oxides in the exhaust. When oxalic acid damages it, all these pollutants exceed the limits. I've seen cars fail emission tests and waste money replacing the catalytic converter. The converter's lifespan is already short, and oxalic acid not only accelerates its deterioration but may also cause the engine to trigger an emission-related warning. I advise car owners not to attempt cleaning with oxalic acid themselves and to opt for professional maintenance instead.
