Does anyone know the guidance on the LS 430 and flushing the cooling system?
Not just radiator but entire system?
Sometimes this is not recommended.
Any help for me?

 

I am also interested in this answer.
Can you please add which type of coolant to use.
Some dealer state Pink and other state Red.
From what I understand after 2004 you should use PINK

 

Use Pentosin Pentofrost A1 pre-mixed if you want a superior to factory fill, you may also use A4 if you desire longer service interval.

To drain it you can simply open the rad drains, and then the block drains, they are not too hard to get to but do NOT attempt to open them if they are rusted and fight. If you can't open the block drains then use a vaccum extractor on the rad hoses from the engine. Kinda a pain to do but it will get most everything out....

 

You can also just remove the thermostat (so it is free flowing) and do multiple radiator drain and fills. I think ChrisFix on uTube does a pretty good job of it.