Thanks alot for this details I find it is very useful and most probably I will go for the coolant delete now but not change the bearing as the whining sound is not that bad :D
I will check if I can do it myself, are their any video shows the steps to install coolant delete in our Mercedes B class, can't it be done only from the side without removing the motor?
This is exactly the reason that I want to install coolant delete as I am concerned that the motor to be damaged if I have a leakage, I have checked the speed sensor and it was relatively dry but I have hear whining in the motor