DD15 not going in to Low temp regen after Changing the EGR cooler.

I have 2014/DD15/DT12/827K miles on it, Coolent reservoir (surge tank) was leak due to over stress and had multipal leaks changed the reservire, also was Eating the Coolent every thirty t forty mile about a gallon coolant Drove about 170 miles to get to the shop.
After changing the EGR cooler blowing excessive white smoke and it is not going in to low temp Regen. Dealer said further need to take out DPF filters and check the one Box, advised not to drive in this condition.
Also oil level was too high as coolent escpaped to engein, hade to replace the oil and oil filters
any advice ? truck still in shop