Radiator fan on loud when driving

[Aaron19771977]

Radiator Fan always on and when driving it gets louder/faster then stopping it goes lower speed but still on, changed the coolant sensor on front of engine today and still got the problem , i had the dpf recently gutted and deleted , not sure if that has anything to do with it , no signs of over heating , temp sits at about 100 at normal driving speed - checked pressing button for hidding menu, no coolant loss and coolant level good, no codes either in ista, any help appreciated

[Aaron19771977]

Also Is it normal for the water to trickle back to expansion tank on cold start? 
Also bleeding electronic process not working on car when holding accelerator down, I thought engine temp must get hot to open thermostat before it trickles back 

[Greydog]

Morning Aaron

Water circulating short answer, Yes

The Auxiliary water pump circulates water around the top of the engine until the thermostat is open fully

I don't know why you had the DPF messed with, a vigilant MOT tester will fail the car if its spotted. It is also quite probably the reason for your fan running. The fan is triggered when the DPF is in Regeneration so if some of the DPF sensors are reading regen conditions then that is your problem

Dave