A search showing Gen 3 can be use with Long Life Coolant but can only last 30K miles while Super Long Life Coolant last 50K miles. Since my 2013 Prius had Super Long Life Coolant in system. Even if I drain and refill with LLC on my 2013 prius, I could mixed with SLLC and LLC in my coolant system. That's no way to completely drain all the SLLC out on inventer and engine right? I purchase the LLC on amazon by mistake, should I use it? It need be mix 50/50 with distill water. I also has asked Toyota Dealer, they offer LLC and SLLC. for 2013 Prius.
This is correct. However as already pointed out, the change interval for the factory fill is 100K miles. It is OK to mix the LLC and SLLC. It is correct that the engine coolant loop will contain some old coolant after a drain, perhaps 1/3 of the total capacity. The inverter/transaxle will mostly be drained. You can use the LLC if you are willing to observe the 30K mile change interval.