Talk to me about the PCV valve. I know that all piston engines have some small amount of blow-by, where a tiny bit of combustion gasses get past the rings, and into the crankcase. These gasses build up the air pressure in the crankcase, and if un-vented, this pressure will eventually blow out a gasket or an oil seal, and create an oil leak. Back in like the 60's, they just stuck a little elbow pipe in the side of the block, and vented the crankcase straight to the atmosphere. It worked (no EPA regulations back then). In the 70's, to take better care of the environment, they started running the vent tube up to the air intake, routing the crankcase gasses back into the engine to be reburned. This worked too, except this method also sucked oil mist into the intake. So, enter the PCV valve. This valve, as I understand it, is supposed to block the oil mist, and pass through the gasses? What if I'm seeing my PCV valve always covered with oil-- does this mean my valve is bad, or the hoses not sealing well, or what?