Freezing Temps

[Tunnaman88]

Gotcha.. no first method is good.. no heat exchange..

[spareparts]

smoke has it right, if you just run it on the muffs, most of it bypasses the thermostat and runs out the exhuast, best way is to drain it, then run or pour the pink stuff in it. The only reason we use the pink stuff is on salt water boats to keep the rust down

[inaforty]

Interesting that you can just drain the block on a small Mercruiser.

All of the big boats at the boat yard with full inboards always run anti freeze through the raw water side. No different what power.. Mercruiser,Marine Power,Crusader, Cummins,Cat,Detroit,Yanmar all done with anti freeze.

If I trusted draining the block and exchangers I could save a bunch of $$$. I run 9+ gallons thru each engine. Maybe it's done because of the protective qualities in the antifreeze?