GS
I think that you are misinterpreting what I wrote.
Re-read it, and you should see that I am listing the possible problems–as I see them–and in addition to an inoperative cooling fan and trapped air, the use of “straight” water would indeed be a problem.
Just as I am not suggesting that the OP disconnect the cooling fan or try to trap air in the cooling system, I am also not suggesting that the OP use “straight” water. Re-read it, please.