another overheating problem

I did not use a 3 step process, I just got them snug using the proper pattern then torque to spec. So that could be part of it.
I did not flip over my level but did use another straight edge which I use when cutting carpet although rarely use. And both seemed fine.
The gunk was black like and hard like oil gunk that was fired so I assume that is what it is, oil. When I start the car it would always bellow out a cloud of smoke like it had bronchitis and needed to clear it's throat so to speak. White smoke always. So I am guessing coolant getting in the combustion chamber.
The coolant and oil have not mixed from what I've seen. The oil is a bit runny I'm assuming from gas, again it's been a pain to start when cold but not so bad when warm.sometimes fires right up when the ignition is turned over as in u can't just tap the ignition or it would fire right up but not always.