Can anyone help or suggest link or tutorial to most effective coolant flush? I have a '05 F150 FX4.
Is it necessary to flush or is just draining adequate ?

thanks,

 

I always just drain and refill unless I buy an old vehicle that has a rusty system. I use distilled water to mix with the anti-freeze, not tap water. Tap water has minerals that will plate out on the cooling surfaces. I had to replace a heater core one time because I put tap water in the system.

 

Unless your tap water is very high in mineral content, the additives in the coolant should prevent any corrosion and scale.