Can diesel exhaust fluid (DEF) still be used after being stored for two years?
2 Answers
Using substandard DEF can damage the urea pump. Here are the specific details: 1. DEF standards: Compared to domestic industrial urea, DEF production standards are stringent, consisting of 32.5% high-purity urea and 67.5% deionized water, with strict requirements for density, refractive index, alkalinity, metal ions, anions, impurities, etc. Some companies use ordinary water instead of deionized water to reduce production costs, resulting in DEF that fails to meet usage requirements. 2. Storage: The storage period is 36 months when the temperature is ≤10°C; 18 months when ≤25°C; and 12 months when ≤30°C. When using DEF, it is recommended to use products manufactured within six months. If the product has been stored for over a year, it is advised not to use it.
I've been running a repair shop for over ten years. Diesel exhaust fluid (DEF) basically becomes ineffective after two years, with a normal shelf life of about one year. After expiration, it may crystallize or deteriorate. Once, a customer used DEF that had been stored for a long time, resulting in a clogged SCR system and an alarm. They ended up spending three to four thousand to replace the nozzle. My advice is to first check the bottle: if there's sediment when you shake it or a strong smell when you sniff it, don't take the risk. You can also do a simple concentration test—if it's below 32.5%, it's completely unusable. To be safe, don't try to save money on this; just replace it with new fluid. Store DEF in a cool, shaded place, and avoid keeping it in the trunk during summer to prevent high temperatures from accelerating deterioration.
