Re: Extreme Cold
I agree with your observation of the oil radiator. We've had one before and they absolutely do not work in a drafty space. We didn't get one this time because we need quick intense heat for after we have to open the hatch.
I did discover some damage from the extreme cold.
Both caps to my heat exchanger have to be replaced. Fortunately it's a cheap fix. Ice was in there and froze them out bending the caps. I flattened them back out, but the gaskets are shot. I determined I'm just going to replace the whole 3 piece assembly.
Fortunately my impeller isn't bad. There is lots of pressure to the water. If I had more experience in boating, I would have shut off my water intake and ran the water out of the exhaust. I have an closed cooling system, so the engine itself was not damaged by the freeze, just the ends for the heat exchanger.