What happens if the temperature of automotive urea is too high?

[VonElle]

Excessive temperature in automotive urea can lead to an increase in free alkali and free ammonia content. Specific details about automotive urea are as follows: 1. Storage temperature for urea: During transportation, urea should be protected from light and high temperatures. The optimal transportation and storage temperature should be maintained between -5°C and 25°C. 2. Low temperature: Automotive urea will crystallize when the temperature drops, expanding in volume by 7%. Storage rooms should be kept below 90% of the storage capacity. 3. High temperature: High temperatures can cause urea to decompose. Generally, the storage temperature of urea is related to its storage duration.

[DiEmerson]

Excessive temperature of diesel exhaust fluid (DEF) is quite troublesome. When I was driving my diesel truck on long-distance trips, I once encountered a dashboard warning light that scared me into pulling over immediately for inspection. The mechanic later told me that DEF tends to decompose and crystallize under high temperatures, which can clog the injector and pipes, causing the SCR system to fail. Since that incident, I've been particularly careful about parking locations - never leaving my beloved vehicle exposed to direct sunlight, always seeking shaded spots during summer. I heard DEF starts deteriorating when temperatures exceed 35°C, significantly shortening its shelf life. Now I use smaller DEF containers, purchasing only what I need and keeping empty containers tightly sealed. If you notice stronger exhaust odor or reduced engine power, address it immediately - otherwise, the crystallization could ruin the catalytic converter, leading to repair bills running into thousands. Regular SCR system maintenance truly saves both money and headaches.

[Andres]

Last time, several vehicles in our fleet had collective issues, all caused by high urea temperatures. During the scorching summer days with temperatures around 38-39°C, drivers parked their vehicles directly under the sun after trips, turning the urea tanks into virtual steamers. The high heat caused the urea to decompose into ammonia and crystals, completely clogging the nozzles. Once the SCR system failed, the engine went into torque limitation, turning the vehicles into slow-moving snails. The most troublesome part was dealing with the crystallization—having to dismantle the entire system and flush it with professional cleaning agents. Now, I’ve set a rule: fleet vehicles must be parked in shaded areas or garages, and during high-temperature days, regular checks on the urea filters are mandatory. During new driver training, I also emphasize that if the urea tank temperature exceeds the limit, they must never force the vehicle to run; shutting it down immediately to cool is the top priority.

[MalachiLee]

Having repaired diesel vehicles for twenty years, I've seen too many failures caused by excessive urea temperature. The most common issue is nozzle clogging, where white crystals are found upon disassembly. At high temperatures, urea decomposes into solid impurities like biuret, which are also corrosive. One construction vehicle had its urea pump completely jammed by crystals due to prolonged high-temperature operation. Dealing with such faults is laborious, requiring the entire injection system to be disassembled and soaked in acidic cleaning agents. The worst scenario is when crystals contaminate the SCR catalyst, which usually necessitates replacement. I advise vehicle owners to pay attention to three points: park away from direct sunlight in summer, replace the urea filter regularly, and take a few minutes' break every two hours during long-distance driving to let the system cool down.