Replacing antifreeze in 2010 Yaris 1.3 (GB)

[SirDigby]

you just drain from the petcock at the bottom of the radiator. the hose at the bottom runs to the block, so if you want that to drain too, you'd need to get the engine warm, but not super hot, just enough for the thermostat to open. there is no need to use any kind of block cleaner or anything unless you had a leak some where or had some strange coolant in it. if you get a spill-free funnel it's very easy to burp system. it attaches to the radiator cap and allows the system to breathe wile not making a mess.
1.warm-up
2.drain
3.fill (recommend factory coolant)