thats exactly what i do. did it on the F150 and Exp. I dont think you get all the water out after draining. Seems like after adding the coolant, i might add 1-1.5 gallons of water, but after checking the strength its in inthe 50-60% range = good.
Last time I changed my coolant in my 99 Ex 4.0 SOHC, after flushing, I put in a total of approx 4 litres of anti freeze and 3.5 liters of de-ionised water after burping. It is still full. My owners manual states the capacity to be 7.4 liters.
Anybody know how much the cooling system holds in a 1999 Explorer?
I have searched all over and can't find any numbers. The person at the parts store said 15.8 QTS but that seemed a little high to me.
If it is almost 16 QTS (4 gallons) could I just drain and flush the entire system (run the engine with the heater on) several times until the water runs out clear.
Then add 2 gallons of straight coolant (because I have heard that the system can't be totally drained without pulling the block drains) and top off with water to get about a 50/50 mix.
No, because you are never supposed to put tap water into the system. Tap water contains minerals that react with the metal in the system and can plug up the heater core and radiator. Pure water is a poor electrolyte, so combined with the corrosion inhibitors of the antifreeze, the system stays in pristine condition. Minerals are required to make water into a good electrolyte. This results in electrical corrosion and galvanization of the metal parts.
Even though it seems a waste, premixed coolant is a bargain. It is pure mineral free water with the correct amount of coolant already in it. Unless you already have an RO system or a water still or some other readily available source of purified water, the premixed coolant is the way to go. Plus it is convenient, I always carry a gallon in my vehicle in case of an emergency.
Now you can use tap water to flush the system, but you should not leave any in there. So after flushing, the system, drain the water out. To get it all out, you will have to waste some antifreeze. The system should not need to be flushed unless the system has already been neglected. If you change the coolant every other year with pure water and antifreeze, the corrosion should be so minimal that it will just drain out with the old coolant.