I'm thinking of doing a full system flush soon, as I strongly suspect the coolant quality to be questionable to say the least. Anyway, what I have in mind is:
1. Make an improvised flushing machine, basically an electric powered water pump, some piping and a few taps, some hoses to connect it to the cooling system. Ideally add some reservoir with a heating element in it, as hot water with some flushing agent works real good. I want this thing to be able to switch the flow direction between the two ports so I could do both reverse and normal flow flushing. Seen a similar device in one of the local shops, they use it to flush the heater cores. Crude, but it really gets the job done.
2. Drain the system from the rad and the heater core, leave the block plugs alone.
3. Remove the T-stat
4. Flush the radiator, the block and the heater core separately from each other. Heater core is easy enough, the radiator too. I'm a bit worried about the block, but theoretically - having the flow generated by an external pump via the top and bottom hoses is sort of the same as having the engine water pump running.
5. Get as much water out of each of the components as possible.
6. Reconnect everything, refill and burp the system.
This in my opinion should get most of the debris out of the system. Any opinions on further improving this plan?