I have a 2003 Ford explorer 4.0 liter and it has 161000 miles on it and the radiator fluid has never been changed.>>>>>>>>>>>>
That is way too long to go before changing engine coolant.
>>>>>>>>>>>>>>>I was wondering if anyone on here could give me directions on how to do this? I read on online that I could take off the bottom radiator hose and let it drain out and then stick a water hose in the top radiator hose and flush out the whole thing can I do it? I just want a way to clean out the whole cooling system and the radiator and get all of the junk "out of it. Thanks!>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Taking off the bottom radiator hose won't flush out the heater core. It will just empty the radiator faster than thru the petcock. The Haynes Manual says to remove the expansion tank cap and drain out the old coolant first thru the petcock or as much as you can get to come out. Then remove the Thermostat and re-install the t-stat housing without the t-stat and remove the top radiator hose at the radiator ,and insert a garden hose into the rad opening and turn on the water. The old coolant will then be forced down thru the radiator and up thru the water pump, up thru the cylinder heads and back past the removed t-stat and then out of the system thru the opened end of the upper rad hose where you disconnected it at from the rad. The manual doesn't specify if this method flushes out the heater core, but it will flush out the whole engine block and radiator. There is a heater core flush kit made by Prestone that you can connect into the heater core hose and connect up a garden hose to the Prestone kit T-connection, and flush out the heater core that way. Once you get nothing but clear water coming out, you are done flushing the system.
Now drain out as much of the clean water as you can and close the petcock, re-connect your upper radiator hose to radiator, install a "new" t-stat (2003 V-6 t-stat is temp range 194 to 210 F degrees) and use a new O-ring seal. Tighten the t-stat housing bolts to 89 inch lbs of torque. Use a torque wrench to tighten down the bolts. Once that is done, start re-filling the system thru the expansion tank with at least a 50/50 mix of coolant and "distilled" water. Go with a 60 coolant/40 water mix if you live in an extreme temp area. Remember there is some plain water still in the engine and or heater core, so test the coolant mix just before final topping off for proper, temp protection level. Prestone also sells a coolant tester, think it's called a "Hydrometer"? Once filled up to the full level mark on your expansion tank, start the engine with the inside heater controls turned to hot temp, blower fan on high and wait for the engine to heat up and open the t-stat. Once the t-stat opens (look at engine temp gauge for normal operating range), start feeling dash vents for hot air and you should see the fluid level drop in the expansion tank while the engine sucks in more coolant thru it after the t-stat opened up. Add more coolant when this happens to expansion tank and fill it back up to the full mark. Install the expansion tank cap now and keeping checking the dash vents for proper heat. If you get good heat and the expansion tank is to the full mark, you are done. Check for any leaks. ( Always re-check the coolant level in the expansion tank the next day after you ran the vehicle and it had time over night to totally cool down. It may or may not suck in more coolant thru the system. Add more if necessary. If not getting heat thru the vents, you may have air in the system from the draining and refilling process. If this happens, start squeezing the upper radiator hose by hand to expell any air from the system. Wear work gloves to protect your hands and keep your hands away from any moving engine parts, fan/pulleys and belt. Keep doing this till you don't see any more air bubbles coming up in the expansion tank. Check for heat again at the dash vents. If no heat yet, take it for a short drive leaving the heater set to hot temp and fan on high speed. This is how I did my flush and fill on my 2005 Explorer V-6 last May and how I got rid of air in the system and it worked for me. Only thing is, I didn't flush out the entire system like you want to do and I didn't remove the t-stat for flushing out purposes, just replaced it with a new one and I didn't do the upper radiator hose removal for garden hose flushing. I just opened the petcock and drained out 2 3/4 gallons of old coolant, flushed expansion tank and radiator by flushing with clean water from a hose at the expansion tank, then drained to clear, and refilled with new coolant. My old coolant wasn't that old and was clean. BTW, the entire system without auxillary climate controls( no rear heat), holds 16.3 quarts and if you do have auxillary climate controls(with rear heat), it holds 18.2 quarts. Each year I will drain and add 1 gallon of fresh coolant to keep the system fresh and up to proper protection levels along with good water pump lubrication just as regular maintenance. Hope this info helps with your coolant change.
