The Nissan Path

Does anyone have experience power flushing their coolant system?

I'm talking the soap & water flush, then sulfamic acid & flush, then oxalic acid & flush, then baking soda to neutralize, then distilled H20 flush.

Bypass the heater core, remove the thermostat, anything I'm missing? Maybe a new head gasket before?

Maddgo..
this sounds like something me and a roomie did many years ago on an ancient BMW.
And in theory it should do some good.

But I will defer commentary to our proper resident expert smj.

Are you having overheat issues? Or just leery of extra deposits in the nooks and crannies of your cooling system?

I had fixed a coolant leak earlier. But then I saw that more coolant was leaking after I had stopped the vehicle. Seemed like the coolant leak was cuz of the water pump going bad.

It was about that time for the timing belt anyways, so I decided to bite the bullet. On teardown saw that the thermostat either rusted shut or perhaps closed permanently after earlier overheating. Wanted to clean that sucker out before I put the new water pump in there

Many questionable things have been uncovered, such as finding the end of a wire brush in one of the air pipes in the front.

nothing sketchy about the wire brush. its supposed to be in there

Yes, the "wire brush" is factory installed and is called a "flame arrestor."