"Bullshit. There is NO PATH from the combustion chamber into "the valve cover area". You ever heard of VALVE SEALS???"
Hold the fertilizer and stay with me here for a bit; the intake manifold distributes the air/fuel charge to the cylinders via runners which extend into the area beneath the valve covers which are ventilated by the PCV valve on normally aspirated engines and often by a "gulp valve" on blown engines which runs from the valve cover to the exhaust purging the crankcase due to the negative pressure pulses present.
The runners are ports to the intake valves and operate much cooler than the exhaust runners or the combustion chamber and can easily cause sweating of the ambient air being drawn into this area betweeen the head and the cover; when the engine is shut down this area heats up by soaking and then can cool down again to ambient temperature which allows condensation that could fall through the oil drainback holes that must be there to allow the oil that feeds the upper valve train to return to the crankcase.
No argument is being made that water is condensing in the combustion chamber although gobs of water is being produced in the exhaust by combustion and it is not this water that contaminates the oil.
On methanol engines it is critical that the engine oil operate above 225F but below the smoke point in order to prevent excess wear to the iron components and absent an oil heater a good deal of moisture could likely form in the engine oil.
Sigh---I tell you again--there IS no connection of the oil-containing region under the valve covers to the outside air except for the TINY amount of air that is drawn in by the PCV valve--most of the air volume in the "oil" volume recirculates and is at engine temperature (thus any water that "might" come in thru the PCV valve will evaporate instantly). This region is totally isolated into it's own independent region/volume within the engine by a multitude of seals. The "runners" are completely isolated from this volume. I think you'll also find in most engines that a major portion of this "intake runner" runs through a water-jacketed area, and is heated there, as well.