Well, the best is too fully drain the system, flush with fresh water, fully drain the system again, then fill with 50/50 of the "correct" anti-freeze and "distilled" water.
The newer engines and cooling systems get hard to fully drain, but just draining at the radiator plug now-a-days barely gets half the coolant out. That is why there is such a complicated procedure. Especially if you have the rear climate control, you'll have a lot of coolant trapped in the lines and rear heater core.
Opening the bleed port and filling from there is a MUST, you'll get trapped air otherwise and enough trapped air you'll likely overheat before it works it way out of the system.
I do NOT have a Hemi, but have done this on plenty of vehicles and it seems to work well, but you need an air compressor, perhaps improvising with a tube and blowing with your mouth might be enough pressure.
Leave the radiator cap on, drain from the radiator drain, this will form a vacuum and suck all the old coolant out of the overflow tank, once the overflow tank is empty you can pop the radiator cap and it will drain more quickly.
Disconnect the lower radiator hose, NOT sure on the Hemi, but the powertech engines the thermostat is in the neck to the lower radiator hose. I always replace the thermostat with a new one at coolant changes, so I just unbolt the lower neck and pull it to change the thermostat. That will get out a lot of coolant still trapped at the low points and the engine.
I remove a heater hose to the front heater core and use compress air to blow out the coolant in the heater core and the line, doesn't take much presure, you could hook up a hose and probably do this with your lungs alone if you don't have an air compressor. If you have a rear heater, I use a vice grips to clamp off one section of hose to force pressure down the other side of the "T" in the heater hoses and flush out the coolant from the rear lines and heater core.
Finally is the last bit of coolant left in the water jackets in the engine block. Some engines it an extreme pain to pull these and its only the last 5 to 10% of the coolant left trapped in there. So if you blow this off, your still doing good and getting a good amount of new coolant to protect the system in the vehicle. For my 3.7L Commander, I found compressed air sprayed down the bleed port actually forced all the coolant left in at the bottom of the water jacket. Of course I still had the lower neck removed with the thermostat out, so there was little resistance to the wave of coolant created coming out from the compressed air, the thermostat is still in, I doubt anything is going to get past it. Don't know if that will work on the Hemi or the 4.7L V8, but worth a try if you have an air compressor.
Hate to say, I know its a pain, but if you've got rear heat, if you just pull the radiator drain, I'm guessing you're only going to drain less than half the coolant, you're going to have to drain the overflow tank, at least pull lower hoses and blow out the heater lines/cores to get a good 90% or more of it.
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Last edited by Mongo; 08-04-2014 at 03:47 PM.