Sorry chaps but I’m not convinced the louvers are the main culprit. I don’t have any bonnet louvers over my plugs. I don’t drive either if there is any rain in the forecast but I do get corroded plugs, as do many louverless Ford owners according to their forums.
Perhaps the culprit is humid crankcase air?
Perhaps the positive pressure can breach the rocker cover sealing?
Perhaps the moisture is sealed in by the plug caps?
Perhaps the tips of the plugs are the first part of an engine to cool when switched off and they become condensation magnets?
