Im installing the sending unit for an autometer water temp gauge and will be removing the stock sending unit thats on the from driver side head. How much coolant will come out?

 

lots

I would, dosent take too long and won't make as much of a mess.

Faded

 

Draining the radiator doesn't help. All it does is drain the radiator. Coolant will still be in the head and there will still be a big mess. Might as well get a big bucket and lots of towels. Ask me how I know.

 

Guess I gotta be fast and stick the new plug in.

 

Famous last words! Sounds good when you think about it but you'd be surprised how fast antifreeze comes gushing out once you get the sensor out. Good luck