The only part of this simple job that has me concerned is if the plastic drain valve breaks when I loosen it. It will be a PITA getting it out since it's not easy to access.

Aside from that, the LR service manual says to disconnect the neg battery terminal before performing the drain. I've seen similar instructions for other vehicles. Why does the battery need to be disconnected? The only reason I could think of is to prevent accidental starting while the radiator is empty.

 

The battery disconnect is probably a general safety thing. On some cars it's possible to cause the starter to crank by accidentally shorting an exposed terminal to ground with a tool, not sure about this one though. If you want to be safe but keep your radio memory, etc alive you can hook up a small 12v battery or a low-amp power source... won't provide enough current hurt you.

A 9V battery might be enough, not sure. You can get an adapter for that like this one, you'd need to plug it into the REAR console cigarette lighter outlet since the front one is only powered when the car is one. The rear one is always powered for some reason.
https://www.tooldiscounter.com/produ...4aAptSEALw_wcB

I have a small power source for electronics hobby use, selectable 6 or 12v, fused for maybe 5 amp that I made myself years ago. You can buy things like that too.

My 2008 has had the coolant changed twice, once within the last few years so I don't think those valves are prone to sticking and failure, probably why they used nylon instead of metal in the first place. Just make sure you're parked so you can get a tow truck to it haha.

 

Thanks! I have one of those battery memory savers that connects to the OBD2 port.

A lot of modern vehicles (newer than our 08) don't have cig lighter adapters anymore. They've disappeared along with the 8-track player.

 

Nah, they just call them accessory ports or plugs now.