What to Do When Automotive Urea Freezes?
2 Answers
Automotive urea freezing can be addressed by: adding a vehicle urea modifier to lower the freezing point of the urea solution, or using an external heating device to thaw it. Northern version vehicles equipped with SCR systems come with a built-in urea tank thawing and heating function. When the engine coolant temperature reaches 60 degrees Celsius and the urea solution temperature is below minus 5 degrees Celsius, the system will not inject urea solution in low-temperature conditions, thereby providing sufficient time to thaw the crystallized urea solution. Automotive urea is used in the selective catalytic reduction (SCR) system of diesel vehicles to catalytically reduce nitrogen oxides in the exhaust into harmless nitrogen and water, thereby reducing nitrogen oxide emissions from diesel engines, offering energy-saving and environmental benefits.
I encountered this situation before when driving in winter - my diesel car's urea system froze up and the warning light stayed on. As the owner, I know urea is prone to freezing in low temperatures, especially below zero. The solution is not to panic. First find a safe place to park, turn off the engine and wait a few minutes for it to thaw naturally. After restarting, let the engine idle - the heat will gradually melt the ice through the urea tank heater. Don't rush to drive to avoid damaging the SCR system. Since then I've learned my lesson: in winter, buy special anti-freeze urea or add anti-crystallization additives, try to park in garages to avoid cold, and regularly check urea levels and system status. The repair costs after one freeze can be hefty, so I advise everyone not to take it lightly - developing good habits saves trouble.
