How to Clean a Clogged Car Urea System?

[OMaci]

Urea solution undergoes hydrolysis in an aqueous solution at temperatures between 70-75°C. Maintain the water temperature above 80 degrees and soak the nozzle head for more than 30 minutes. Place the urea nozzle in an ultrasonic cleaner and clean it for more than 15 minutes. After turning off the vehicle's ignition, do not immediately shut off the main power supply. At this time, the urea in the nozzle and pipes will flow back into the urea tank, which requires some time.

[CassidyFitz]

Last time my truck's urea injector got clogged, I directly removed the nozzle and soaked it in hot water for half an hour until the urea crystals softened, then slowly cleared it with a fine needle. Remember to wear gloves—this job is both dirty and labor-intensive. After finishing, you also need to flush the lines; get a clean bucket of distilled water and cycle it through several times. I usually disassemble and inspect the nozzle every three months to avoid sudden breakdowns during long hauls. If you encounter this situation on the road, don’t force the vehicle to keep running—a damaged SCR system will limit power, so pull over and address it immediately. Always use reputable brands when adding urea; don’t cheap out and buy from small workshops.

[DiWalter]

I've handled urea clog cleaning on hundreds of vehicles, and thoroughness is key. First, disconnect the urea pump's power supply, remove the nozzle and filter screen, and use an ultrasonic cleaner to vibrate away deposits. For the piping section, use a pressure gun to spray specialized cleaning agent, repeating the flush until the outflow runs clear. Remember to simultaneously check the urea pump for crystallization – blockages here are the most troublesome. I recommend performing a major maintenance before winter each year: completely drain and thoroughly clean the urea tank, and replace the filter. Many owners rush back on the road without proper cleaning, only to get warning alerts after 300 kilometers, which ends up costing more.

[EzraDella]

Our fleet follows a three-step routine to clear urea blockages. First, pour two bottles of dedicated cleaning fluid into the empty urea tank and let the engine idle for 20 minutes to dissolve crystals. Then, disconnect the nozzle and blow out the lines with a high-pressure air gun. Finally, fill the system with purified water for a flushing cycle. The entire process takes 40 minutes, which is more convenient than disassembling parts. Key maintenance tips: Allow the urea pump to run for an extra 10 seconds before shutting down to empty the lines; avoid mixing urea brands; replace the filter every 20,000 km. Following these details can significantly reduce blockage risks.