Hydro Lock

Very common for upper intake (black plastic) to fail on this 3.8L, what happens is there is a egr pipe that comes up into the upper intake, the pastic around the pipe gets burned over time and melts causeing the coolant channel in the intake to rupture flooding the cylinders with coolant causing hydrolock, the replacement upper intake will come with a redesigned egr pipe to prevent it from happening again.

the plastic that melts is it noticable? did not really see any obvious signs - did not look bad?

Only noticeable after removal, on the inside of the upper intake, if you pull that upper intake off and it is full of coolant underneath, that upper intake will be the culprit.

Ok we have done everything turned it over Smoke was burning off temperature was fine drove it fine. Turn on today and let run and the smoke was gone but now the check engine light came on - do you think changing the oil after all this will help? Any other helpful thoughts?

YES, change the oil now, there is surely some coolant in the crankcase oil, and that is not good, get it changed because it can cause engine failure. antifreeze is like sandpaper on bearings. The check engine light is probaly for o2 sensors because of the antifreeze in the exhaust, but you would have to get it scanned to know for sure.