While topping off my anti freeze this AM I overfilled about an inch above the cold fill line. Should I suction it out or will it go out the over flow hose when it gets hot, Cat C7 engine.
I would not worry about a little over the cold line fill. Like said, it will replace air in the system or bleed out the overfill and be gone after your next run if it is long enough and the engine gets hot enough. Now if you are having to add on a regular basis, I might make an effort to solve that problem before it becomes a bigger issue!
Though you might want to wash the area under the antifreeze to clean it off of the RV. Little known is that dry antifreeze can catch fire. Hopefully the overflow will drain through a tube to the ground.
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
No problem, don't give it a second thought. If it is too high, it will purge the small overfilled amount out the overflow to seek its natural full level.