Have a S10 Blazer with the 4.3. It's getting moisture inside the oil filler cap, but the dipstick remains clean-no milk. What gives?

 

Depending on how short your trips typically are, this could be completely normal. If the engine doesn't fully reach a steady state temperature throughout the entire engine (not just the cooling system), it may not be burning off moisture from the environment that enters the system when it cools.