I drained radiator, vacuumed reservoir. Added prestone cleaner with water. Drove 2 hours-ish. Drained cleaner (it was quite dirty). Flushed radiator out with water until water was clear. Drained/vacuumed again. Started adding concentrate but was only able to add 1 gallon. From what I've read, I should have been able to add 1.5 gallons along with .5 gallons of water for 3 total (including the water that was left in the engine from the flush). Any thoughts on why I couldn't add the rest of the mixture? According to the procedures I've read, I'm not a little off. I'm way off. An entire gallon.

Having said that, I have now driven for about a week and have watched the temps/reservoir closely and no change. I'm just concerned the mixture is off. If there were actually 2 gallons of water in the system after the flush, then the mixture is ~66% water instead of 50% water.

 

Draining a cooling system through the radiator alone does not allow the coolant in the block to exit since the level is not allowed to fall lower than the upper connection of the lower radiator hose..Most engine blocks have separate drains for the engine block to be drained.