Can Boiling Water Remove Urea Crystals?

[Harmony]

Boiling water can remove urea crystals. Whether it's urea crystals inside the urea system or in the exhaust pipe, boiling water can be used to dissolve them. First, remove the injector nozzle from the urea system, then soak it in hot water at around 80 degrees Celsius to dissolve the urea crystals blocking the nozzle. It's also important to clean the urea tank regularly, as sediment often accumulates at the bottom, which can affect the smooth operation of the urea injector. If the urea crystallization in the exhaust pipe is not severe, pouring 80-degree Celsius hot water into the pipe can dissolve the crystals. For larger crystal deposits, the rear section of the exhaust pipe may need to be removed for repair. To prevent urea crystallization in the exhaust pipe, measures such as insulating the outer wall of the pipe, increasing the urea injection temperature, and adjusting driving habits can be effective. Urea crystallization in the exhaust pipe is more common in winter due to the significant temperature difference between the inside and outside of the pipe, leading to wet wall phenomena inside the pipe.

[DeSkylar]

I've seen many fellow car enthusiasts ask about this. Last week, I tried using boiling water to flush out urea crystallization myself, but it didn't work very well. The SCR nozzle of my old diesel car was clogged, and I thought hot water could dissolve it. After pouring it down, the surface of the crystallization softened, but the inside remained hard as a rock, actually making the water flow worse. Later, a mechanic told me that urea has a melting point of 132°C, and boiling water at just 100°C isn't enough. Instead, using 60°C warm water with alkaline detergent and slowly flushing it out is more cost-effective and safer. Normally, you should use genuine AdBlue and avoid inferior products, checking the emissions every five thousand kilometers. Otherwise, excessive crystallization can cause blockages, leading to excessive exhaust emissions and increased fuel consumption. After that ordeal, I learned my lesson and now prioritize prevention, regularly cleaning the nozzle to avoid trouble.

[DiJude]

I find that using boiling water to remove urea crystals is less than satisfactory. Since the melting point of urea crystals is higher than the boiling temperature, pouring boiling water only slightly dissolves the surface layer, leaving the interior residue even more stubborn. Additionally, the rubber tubing in the SCR system is prone to aging and cracking. I've experimented at home by flushing simulated urea blocks with boiling water, and it was time-consuming and labor-intensive, far less efficient than using a professional warm water flushing machine. I recommend drivers try a mix of 50-70°C hot water with a detergent, soak for a few minutes, and then rinse thoroughly—it saves time and prevents damage. Remember, don’t cut corners on vehicle maintenance. Regularly replace AdBlue and clean the exhaust pipe to avoid excessive crystal buildup and costly engine repairs. This method is simple and practical, suitable for routine care.

[LeChristian]

From my experience, boiling water treatment for urea crystallization isn't reliable. SCR system crystallization is often caused by low-temperature parking or poor-quality urea. Pouring boiling water may soften the surface but leave the core intact, potentially jamming valves or contaminating sensors. Last time I helped a neighbor, we switched to lukewarm water with baking soda for gentle scrubbing - it came off in minutes without damaging components. The key is preventing crystal buildup: drive at highway speeds before parking to increase exhaust temperature, and always use high-quality additives. Safety first - avoid reckless boiling water experiments that risk burns or water ingress hazards.