Originally Posted by GoneBoatN
For those of us who store "dry blocked":
So I'm curious who leaves there drain plugs in or out.
and if you use Teflon (tape?) for a sealant liquid.
So it is my understanding that the threads will rust less if you store with the drain bolts in place. Also I use Aviation Form-a-Gasket from Permatex. It does not harden and I've never had a drain plug freeze in place on me. It coats the threads so it will inhibit rust (my thoughts). I see people mention using teflon tape for their drain plugs and I don't understand what the advantage of doing so (other than a little less mess).
My boat is in a garage that also contains the house heater and hot water heater, in an area not prone to freezing. So I'm not horribly worried about a little water that might have been missed when winterizing. I would not think this to be a concern anyways if you drain correctly.
Let another off season debate begin... :D
Anti-sieze works, too. Best practice is to use brass or bronze plugs in cast iron- different metals don't fuse like similar but with some metals, a galvanic reaction occurs, which degrades the metals' integrity- this is the reason anodes are needed for stern-drive boats- the aluminum loses material due to electrostatic imbalance between the water and the engine and the aluminum is the less "noble" material. Zinc is even less noble, so it's sacrificed, for the good of the aluminum.
The longer plugs are allowed to stay in place, the better the chance that they won't come out without damage to them or the cast iron. Both dealerships I worked for removed the plugs and bagged them, attaching the bag to the throttle or the steering wheel- it was standard practice so it didn't matter who summerized the boat- we always knew where to look for them in Spring. This was done to all boats, unless the customer specifically requested that we re-install them. Obviously, if anti-freeze was used, they stayed in place. Leaving them out also eliminates the chance that any water that may have remained can't move if the boat is trailered from the dealership, settling in a low spot and causing damage by freezing.