Is Washing the Three-Way Catalytic Converter with Water Effective?

[DiArianna]

Washing the three-way catalytic converter with water is ineffective; specialized three-way catalytic converter cleaners must be used. The three-way catalytic converter is an external purification device installed in the vehicle's exhaust system. It transforms harmful gases such as carbon monoxide, hydrocarbons, and nitrogen oxides emitted from the vehicle's exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions, thereby purifying the vehicle's exhaust. Methods for cleaning the three-way catalytic converter: 1. Additive cleaning: Simply add the cleaning additive to the fuel tank. 2. Drip cleaning: Connect a hose to the engine's vacuum pipe, utilizing the negative pressure in the vacuum pipe to draw the cleaning agent from the drip bottle into the engine. The cleaning agent then cleans the three-way catalytic converter as it passes through the exhaust pipe. 3. Removal cleaning: Remove the three-way catalytic converter and soak it in oxalic acid for cleaning.

[CourtneyLee]

Last time my friend's car had the engine light on, he actually used a water hose to forcefully flush the exhaust pipe targeting the catalytic converter. As a result, right after hitting the road, the exhaust started making gurgling noises. I immediately told him to stop and check, only to find several cracks in the ceramic substrate. The structure of a catalytic converter is like a dense honeycomb, and water pressure can cause the ceramic body to shatter. Moreover, the lead compounds inside can clump together and can't be washed away. For an effective cleaning, you need to use professional carbon remover for soaking, or remove the catalytic converter and circulate an oxalic acid solution for rinsing. After cleaning, you must use a high-pressure air gun to blow out the residue in reverse. Don’t follow those DIY methods taught in short videos—replacing an original catalytic converter can cost four to five thousand yuan!

[LaFernando]

My car repair experience is: Washing the catalytic converter is worse than not washing it. The core of the converter is the platinum-rhodium-palladium metal coating on the ceramic substrate. When carbon deposits clog the pores, water flow can actually harden the carbon deposits. I've encountered cases where white smoke appeared after washing, which was actually water trapped in the muffler unable to drain. To truly solve clogging issues, I first read the fault codes. If exhaust data exceeds standards, I use an endoscope probe inserted through the oxygen sensor hole to observe the level of honeycomb clogging. For mild carbon buildup, I use specialized cleaning agents with an IV bottle for two hours of idling. For severe clogs, it must be removed and cleaned with ultrasonic equipment for 12 hours, achieving about 80% restoration.

[McGabriella]

Once thought water washing could save money, but learned the hard way. The three-way catalytic converter operates at temperatures up to 400°C, and cold water impact can cause metal casing shrinkage and deformation. Calcium and magnesium ions in water form scale at high temperatures, which instead covers the precious metal coating. Effective cleaning must follow steps: first use an infrared thermometer to confirm the converter reaches operating temperature, connect an exhaust gas analyzer to record data, then inject chemical cleaner containing surfactants, and keep the engine running at 2500 RPM for ten minutes. After completion, compare the data—HC values typically drop by over 15%.

[DelBradley]

The catalytic converter structure is too intricate, with honeycomb channels finer than a needle tip. Water flow can't penetrate the deep layers, instead easily causing the front ceramic body to absorb moisture and crumble. Once I saw technicians handling a low catalytic efficiency issue: first removing the oxygen sensor, connecting a pressure gauge to measure backpressure. Exceeding 0.35bar indicates severe clogging. They used a three-way connector to link compressed air and cleaning solution, employing pulsed impacts to dissolve sulfur-phosphorus compounds. Post-treatment exhaust tests showed CO levels dropping from 1.2% to 0.03% - that's scientific cleaning.