What Are the Solutions for Urea Crystallization in the Exhaust Pipe?
2 Answers
Change the layout and direction of the exhaust pipe, repair the injection system, clean the crystallization in the exhaust pipe, or alter driving habits to resolve the issue. Below are the reasons for urea crystallization in the exhaust pipe: 1. Unreasonable exhaust pipe layout: After urea is injected, localized vortices or areas with low gas flow velocity can cause urea solution spray to crystallize in the exhaust pipe. If not addressed promptly, this can lead to exhaust pipe blockage. This situation requires modifying the exhaust pipe layout and direction. 2. Faulty urea injection system: Poor spray atomization prevents urea from fully decomposing and evaporating, leaving residue that crystallizes on the exhaust pipe wall. Repairing the injection system can resolve this issue. 3. Cold weather: If the external temperature is very low, the exhaust pipe wall temperature will also be very low, making it difficult for the injected urea to evaporate. This results in crystallization on the inner wall of the exhaust pipe. This is a common occurrence and may not necessarily indicate a fault. Simply cleaning the crystallization in the exhaust pipe or changing driving habits can resolve the issue.
Urea crystallization in the exhaust pipe is indeed common, and I believe the main solutions are cleaning and prevention. Don’t rush to drive—park in a safe place and wait for the engine to cool before handling it. If crystallization occurs, you can rinse the inside of the exhaust pipe and the nozzle with warm water and a small amount of soap. Be gentle and avoid using a high-pressure water gun, as it can easily damage parts. For severe clogs, it’s best to visit a professional repair shop—they have specialized cleaning agents and equipment to get it clean. Always use genuine urea fluid like AdBlue; don’t cut corners with cheap, low-quality alternatives, as they tend to crystallize more easily. Driving habits also matter: avoid prolonged idling or frequent short trips with frequent starts and stops, as these accelerate urea deposits. Take a highway drive once a week to raise the exhaust temperature, which helps burn off residue. I also recommend checking the SCR system every three months for leaks or blockages—it can save you major trouble. When handling it yourself, be careful and wear gloves for safety—that’s the top priority.
