yep, coolant is there to increase the boiling point, water will boil and increase pressure at 90-100 isn, coolant with a 50 mix coolant and water will exceed this, thats why its there

look at a product called evans waterless coolant thats good or just 50/50 of normal coolant, also having just water increases corrosion caused by oxygen in the engine and radiator

you should really know this