AdBlue is a mixture of urea and water that is stored separately from fuel in many diesel cars registered after 2015. It is squirted into the exhaust to reduce NOx emissions by turning it into harmless nitrogen and water. Cars that use AdBlue technology include recent diesel models from Audi, BMW, Citroen, Jaguar, Land Rover, Mercedes-Benz and Peugeot, as indicated sometimes by terms like "Blue" or "SCR" in the model name. Putting diesel in a gasoline engine will prevent combustion from occurring properly due to diesel's higher viscosity and compression needs. Putting gasoline in a diesel engine will initially allow normal combustion but lead to abnormal detonation and damage as temperatures rise excess