xpro

I am planning to change my coolant soon. I find draining the coolant from the engine block a bit difficult and I want to approach the process a little differently.

1. Drain the radiator and reservoir
2. Fill radiator and reservoir with distilled water.
3. Run car until normal operating temperature
4. Repeat 1-3 until most coolant is gone
5. Fill with concentrate coolant.

Does the process above require bleeding? Do I have the process correct?

Clutchless

Don't do that. You don't need to drain the engine block, or do the distilled water steps, or use concentrate coolant. You only want to use Toyota Long Life Coolant which is already premixed.
Just drain out what you can from the radiator and fill it back up with Toyota Long Life Coolant and bleed it as described in the videos below from the Car Care Nut who is a Toyota Master Tech.

It is too hard to get at and too hard to try to loosen the engine block bolts up for minimal gains. Just drain the radiator, then fill it back up with Toyota Long Life Coolant and follow the method described by the Car Care Nut on youtube. You will replace enough coolant to refresh your system.
He has a terrific trick for bleeding the coolant system on the 3.5 V6 motor. He has a lot more videos on other maintenance.

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ColAngus

I've done the insane thing OP described on my Nissan and I don't recommend. So much work and screwing around. I think I burned myself a few times.
Just overthinking it something fierce.

doji

Drain and fill with the OEM coolant. I did not do the final bleed, I just checked the next 3 days after a bit of driving and topped off the overflow tank as air burped out of the system.

xpro

Since I am draining the radiator only, how much coolant should I buy before starting the job?

Clutchless

Get 2 gallons because you don't want to run out of new fluid during the job. You may have to top it up after a few days driving. It is better to have leftover fluid than having to reuse your old stuff because you ran out of new coolant.