In this video i explain why diesel cars have Adblue, what it is and how it works on the car.

This is quite simplified, so there are some technical details that may be overlooked or inaccurate. Adblue forever is aqueous urea of which the water evaporates upon injection into the hot exhaust.

On the aftertreatment, i mention the DOC and DPF may be integrated into the same can/exhaust unit. This could also be the case for the DPF and SCR filter.

I also overlooked the fact that there are sensors in the adblue tank measuring the quality. It can identify if another liquid (like pure water) is in the tank, and hence it will not inject, and the vehicle will behave like it has no adblue.

Adblue can freeze below -7degC, some cars have heaters to defrost the urea.