- Oct 18, 2008
- 949
- Boat Info
- 1989 340 EC
- Engines
- 7.4LX2 Hurth 630A Drives
6.5Kw QS Genny
Just my .02. Given mine are IB's and I don't run through the drive, but I have RWC engines as well. What I do is warm the engines fully and open my flush valve near the strainer and open the valve which is hooked to a 5 gallon jug with a spigot with pink in it. I then close the seacock and allow the engine to pull in straight antifreeze. I thought about the T-stat slamming shut as soon as the cool antifreeze came into the housing as well. If you think about it though, what is the temp difference in ambient air temp antifreeze and the raw water that is drawn into the seacock? I'm thinking it's pretty darn close. After flushing and pulling one of the block plugs, pink came running out. With the temps I get around here in the winter 0 deg> I would think even if it got in at a 60-40 mix it would still be enough to protect at that level.
