How to Clean the Urea Nozzle?
4 Answers
Urea nozzle cleaning method: Use a small ultrasonic cleaner for cleaning. The following are the symptoms of a clogged urea nozzle: 1. Insufficient vehicle power: While driving, the engine lacks power, giving the driver a feeling of overall weakness. 2. Urea pump not working: During vehicle operation, the urea pump fails to function properly. 3. Urea warning light stays on: While the vehicle is running, the urea fault indicator light on the dashboard remains illuminated. 4. Excessive urea consumption: The urea consumption value exceeds the standard of 10L urea per 100L diesel. 5. Nozzle not working: When the post-processing system is operating, the nozzle does not spray urea, leading to prolonged clogging and crystallization at the nozzle.
I used to clean the urea nozzle by myself. Remember to always disconnect the power cable first—safety comes first. After removing the nozzle, soak it in a dedicated cleaning solution for half an hour. That stuff can dissolve stubborn urea deposits, but don’t use strong corrosive liquids like hydrochloric acid, as they can damage the internal seals. After soaking, gently scrub around the nozzle holes with a soft brush—don’t use a needle! Last time I used a needle and deformed the nozzle hole, so I had to replace the entire nozzle. Finally, blow it dry with a high-pressure air gun, reinstall it, and test the spray pattern. I’ve learned my lesson now—I add a bottle of preventive cleaner to the tank every 5,000 km to avoid constant disassembly. If the deposits are too severe, it’s better to take it to a repair shop—they use ultrasonic cleaners for a more thorough job.
Don't take shortcuts when cleaning the urea nozzle. I've seen people directly spray carburetor cleaner, which ended up corroding the plastic parts of the nozzle. The standard procedure requires first removing the nozzle assembly, preparing a dedicated SCR system cleaning solution, diluting it at a 1:10 ratio with water, and soaking it for two hours. During this process, use a soft cloth to clean carbon deposits on the outer shell, being careful to protect the electrode interface from water. After drying, use compressed air to backflush the nozzle holes until you hear smooth airflow. The key is regular inspection—don't shut off the engine immediately after stopping; let the system automatically flush the lines to reduce crystallization. A clogged nozzle can cause engine torque limitation, and the repair cost could buy three bottles of cleaning solution. Maintenance is more cost-effective than repairs.
Cleaning this thing depends on the situation: For minor crystallization, just buy a can of urea system cleaner, start the engine, pour it into the urea tank, and run for half an hour to dissolve and discharge with the exhaust. If the nozzle is completely clogged, it needs to be removed for treatment. Last time I went to the repair shop and spent 80 bucks. The mechanic soaked the nozzle in a descaling agent for two hours, used ultrasonic waves to shake off the hard deposits, and cleaned the exterior with a brush. If you do it yourself, remember to wear gloves and goggles—the cleaner stings if it splashes on your skin. Before reinstalling, you must test the spray angle; if it's off, it affects the nitrogen oxide treatment. To prevent nozzle clogging, always choose genuine urea fluid with fewer impurities to avoid clumping.
