Disconnect battery for coolant drain?
 

My Haynes manual for 85 300D turbo says to disconnect the negative battery terminal when draining coolant. Not being very car competent, it makes me wonder just what I'm not aware of? I know I 'll have metal tools in my hand, but will I be anywhere close to 12v?

How close is the starter ?

Starter might be close
 

Starter might be close. The manual says there are two drains. The radiator drain pretty much is away from everything. Supposedly right side of engine has some place to drain coolant, but I need to take a better look.

i didn't disconnect the terminal when i removed my rad (convenient way to drain!!) but i would disconnect it whenever working on my car, because of 2 factors:
1 you may find a wire somewhere that will come in contact with your hand, or short and fry something, and
2 "friends"/family thinking "ooh, I'm just going to go and start (your name here)'s car!!! (that was inspired by a dream i had about adjusting valves on my mbz, and my brother tried to start it, crank, metallic grinding noises, and pow!! that probably wouldn't really happen, but its a valid point, and makes me wonder if I'm more paranoid about my car than i think!!)

The two places to drain the coolant are through a drain plug on the right side of the engine block and a plug on the bottom of the radiator.

I have done a number of coolant changes, and can say that I have never heard of diconnecting the battery to drain the coolant.

Yeah its a coa thing... u MIGHT deside to grab the battery termionals with your coolant wettened hands... and that HELLACIOUS 12 volt shock might seriously injure you:)

But the fans (in theory) can kick in at any time, because theyre electric...

Why not disconnect it? takes 5 sec mabey 30... and you dont have to worry about your mother in law trying to start the car with you under it (keep the keys in your POCKET... I kinda spent a while looking for mine... which were in the ignition the whole darn time)

~Nate

If you notice in Haines almost every procedure starts with dicconect the battery. Just Safety.

Including changing floor mats....:D

An ounce of prevention is worth a pound of cure.
 

Ben Franklin:
An ounce of prevention is worth a pound of cure.

Me:
A pound of prevention is 15 ounces too much.

But in this case I'll disconnect the terminal and hopefully remember to wipe off any coolant from my hands before reconnecting.

I always disconnect the battery when working on most things above an oil change under the hood. It's just habit. I'm not worried about shocking myself, I'm worried about destroying some of the electronics on the car. I shock myself all the time (do a lot of the electrical work) and my heart hasn't gone irregular just yet.