If you add adblue to diesel tank what happens?

If you accidentally add AdBlue to a diesel tank, it can cause serious damage to your vehicle's fuel system and engine. AdBlue is a urea-based fluid used in Selective Catalytic Reduction (SCR) systems to reduce harmful nitrogen oxide (NOx) emissions in diesel engines. It is not a fuel additive and should never be mixed with diesel fuel.

When AdBlue is added to the diesel tank, it contaminates the fuel. Since AdBlue is mostly water (about 67.5%) and urea, it does not combust like diesel. Instead, it can cause corrosion in the fuel system, clog injectors, damage the fuel pump, and ultimately lead to engine failure. Even a small amount can be harmful.

If this mistake happens, do not start the engine. Starting the vehicle will circulate the contaminated fuel through the system, increasing the extent of the damage. Instead, contact a qualified mechanic or roadside assistance immediately. The fuel tank must be completely drained and cleaned, and the fuel system may need flushing.

To prevent such accidents, AdBlue and diesel fillers are usually designed to be incompatible in size. However, mistakes can still occur, so always double-check before refueling. Prevention is far less costly than repair.