You really oughta flush your whole cooling system if that's the case. Think of the ramifications. Your heads might have sh!t like that in the water jackets creating hot spots and preventing full heat removal from the combustion chambers. Your heater might work more efficiently, and your radiator could cool the engine better.
The way I do it is jack up the left front corner of the truck and put a small hose underneath the radiator spigot (gotta have the drivers wheel well out) and route it into a pan or a bucket. Then start to loosen the radiator faucet until you achieve proper flow. Watch out on my truck the faucet worked like a POS and didnt really flow until you pulled the plug and sticky damn antifreeze ran down every corner of my truck and made a collossal mess. Once you get the thing drained pull the upper radiator hose off the thermostat neck and start pouring in distilled water there a few times and let it come out the radiator. Distilled water costs $0.50/gal here so I buy as much as I can fit in a shopping cart (gets incredibly heavy, you won't be making any sudden turns trust me

) and pay like $5. Also you can run some distilled water thru the radiator fill cap (make sure to remove that before you start all this and do it with a cool engine so it doesnt burn you).
If you really are feeling adventerous I can tell you how I drained the block, I took some photos, the plugs are so difficult to access you'll either need special tools or removing the starter.
Finally FWIW the Redline Water Wetter seemed to be a total waste of $ on my vehicles, didn't notice any difference whatsoever, just created foam in my cooling system(s) and changed the green color to an ugly pinkish green.