Strange ADBLUE fix

[Steve Walsh]

A mate with a 208 Blue hdi, Just one of many French cars I seem to get involved with for friends and family. For a while he has had adblue faults that wont go away. Usually it is Denox circuit fault or Urea pressure to high, I have drained his tank and refilled with adblue and anti crystal liquid, also removed injector and cleaned the crud from the nozzle, but usually warnings come back withi 100km. I told him it would probably need an injector but he didn't want to buy one...... So I saw him today and he says he has cured it!
He decided to clean out his adblue tank using a aquavac. refilled the tank and fault has gone away and not returned for past month and a few hundred km.....

Figure that one out!

[CitroJim]

That's a good fix! I wonder if the Aquavac sucked up a load of crystals sitting in the bottom of the tank?

[Steve Walsh]

That was my thoughts

[PaulC5]

That is possible. Putting water in could dissolve any crystals whereas only draining and then putting more adblue in may not dissolve them if the solution is already saturated. So if draining the tank it might be best then to flush it out with water, drain it again, have a look inside to make sure it is clean and then put in fresh adblue.