Will mixing a little diesel in the urea solution cause damage?
2 Answers
Diesel and carbon soot from the exhaust can clog the vehicle's treatment system, causing the diesel to burn in the exhaust pipe and even leading to explosions. Below are some additional details: 1. When draining the urea solution from the urea tank: If the urea solution in the tank is found to be substandard, it must be replaced with qualified urea solution. Loosen the urea cap on the urea tank, drain the residual liquid, clean the urea tank thoroughly, and refill it with qualified urea solution. Check the inlet filter screen of the urea tank by opening the urea tank filler port for inspection. If the filter screen is found to be clogged, remove and clean it. 2. Precautions for diesel vehicles: When starting a diesel vehicle, do not press the accelerator pedal, and avoid rapid starts or high engine speeds. After prolonged high-speed operation of the engine, do not shut it off immediately. Instead, let it idle for about 2 minutes to allow the temperature to decrease before shutting it off to prevent heat buildup.
With over a decade of experience in auto repair, I can tell you that mixing diesel into urea solution is a serious problem. Urea is a water-based solution used for emission treatment, while diesel is oil-based. If they mix, it can cause emulsification, clog the injector nozzles, and damage the SCR catalyst, triggering the fault light immediately. You must stop using the vehicle right away and tow it to a professional repair shop to clean the urea tank and replace the fluid. If you keep driving, the pump could seize, and replacing the parts would cost a fortune—at least several thousand dollars. Always double-check the fuel filler inlet when refueling to avoid mixing the two. Regular inspections of the urea system can also prevent unexpected issues—don’t cut corners and end up with bigger problems.
