is it safe to use 100% coolant/antifreeze in your cooling system?

it will not cause corrosion in the system but it will not absorb the heat the same way that we want. you will run the risk of overheating believe it or not. the water is important to pull the heat out of the block.

Only in the reservoir/overflow tank. The engine coolant must have at least a 30% mix with water to activate the anti-rust/anti corrosion chemicals included in the concentrated anti-freeze liquid. Pure anti-freeze will not dissipate heat as well and will give false readings at the sensors. Best idea is to use a 50/50 mix utililizing evaporated,distilled water with a ph around 5.5 to 6.0. You might add a 'water wetter' to this mix for an even better level of heat transfer,from the engine to the radiator.

only if you are way up north like Alaska and at that i would use 5-10 % water antifreeze is not good a heat transfer by its self it needs a little water and it will rust and corrode most of the cooling system

What does it say in your owners manual?

50/50 mix of Dex-Cool and distilled water.

Why? Because the room full of guys with automotive engineering degrees who designed and built your car determined that this works best. Water is much more effective and dissipating heat than straight coolant. If you don't want to blow up your motor use the correct mixture.

Suggest if you use 100% antifreeze it may start to corrode your system

No it's not safe Antifreeze will corrode your cooling system if it is undiluted

DO NOT USE DEXCOOL