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Thanks for the info. Can I pour the anti freeze in the opening where I removed the upper blue “vent” plug on the single point drain system??
Post a few pictures of your system.
In general, for those who are doing this, they are most likely introducing the anti-freeze via the thermostat housing.
If you are absolutely certain that ALL Seawater has been drained, then your anti-freeze protection will very likely be OK.
Also, in your opinion, does the single point drain system get all the water out if I ensure the boat is level on the trailer??
Read what you can regarding complaints about the single point drain systems, then make your own decision.
For me...... I would remove that silly system!
Add anti-freeze to your Raw Water Cooled engine if it gives you that "feel good" feeling.
Note that Anti-freeze may become diluted by any residual seawater.
If you drain it again afterwards, you will ensure that you weren't left with any pocket area dilution!
As said.... just plain ole AIR will not freeze expand and crack our expensive cast iron components!
Never has.... and never will!