Changing coolant/antifreeze closed loop
 

What is the easiest way to change and flush the coolant/antifreeze on closed loop system?
. Boat on trailer
. carbed 540 BBC
. stainless marine Dry to the tip exhaust


Thanks!

Would help to know what motor
Don't know of a "easy way" but not dramatically hard either. Biggest issue is if the boat is in the water or trailer.

Pull block, exhaust manifold, and heat exchanger plugs. Re-Install plugs and fill with water to flush and pull plugs again to drain water.

Plugs back in and add 50/50 mix of AF

There are plugs on the blocks that will need to be drained that should get most of it, but most heat exchangers will have plugs as well. Overflow tank?

Assuming it's a half system you wouldn't have to drain the exhaust/headers.

Be sure to use distilled water and AF. After you fill it back up you will probably have to run it and top it off.