How to Clean the Urea Nozzle?

[LondonLynn]

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.

[VonMaya]

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.

[LaIvan]

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.

[ORyan]

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.

[VonHenry]

The urea nozzle has a quite delicate structure, so extra caution is needed when cleaning it yourself. After disconnecting the pipes, first observe the level of clogging in the spray holes—if there isn't much white crystallization on the surface, soaking it in hot soapy water for half an hour can soften the deposits. However, if there are many hard deposits, you'll need to use an oxalic acid solution (concentration should not exceed 5%), and frequently flip the nozzle during soaking to ensure full contact. The most challenging part to clean is the needle valve gap, which requires gently wiping with a cotton swab dipped in alcohol. Using hard objects to scrape may leave scratches. After cleaning, make sure it's completely dry before reassembly—last time I rushed to reinstall it and ended up short-circuiting the ECU. Now I clean it every 20,000 kilometers without fail, and I never skip adding urea to avoid crystallization.

[MacLyla]

Nozzle clogging is mostly caused by poor urea quality or extended maintenance intervals. I've encountered three failures: the first time using roadside urea solution, it clogged solid within 3,000 km. During cleaning, first disconnect the urea pump power, remove the nozzle and soak it in warm water to soften the crystals, then use a syringe to draw cleaning solution and repeatedly flush the interior. Later I got smarter—switched to automotive-grade urea solution and perform quarterly preventive cleaning: using equipment to backflush the entire SCR line from the urea tank with pressurized cleaning fluid, removing new crystals without disassembly. This protects nozzle lifespan and avoids seal damage from disassembly. For complete disassembly cleaning, it's safer to find a professional technician.