OK guys, what is this crankcase ventilation? This is the first time I have ever heard of this. The symptom I have here is oil leaks on top of my crank case, and oil spots on the hood pad. The gasket on the oil filler cap does look pretty shot but I have no way of knowing if that's what causing all the oil stain on my crank case. Not unless I ride shot gun in the engine compartment. How do I check this ventilation? What effects it has on the engine itself? Thanks for any information.