This morning while the car was warming up, I decided that I would top off the oil because I knew it was about 1/4 of a quart low. I like to keep my vehicles at the MAX level. I took off the oil cap and started to pour in some oil just to find myself getting showered in oil. There was so much air that it sprayed the oil back at me. I place my hand over the oil fill hole and it feels like there is a fan installed under the valve cover. Is it normal to have air pressure flowing from oil fill while its running? I have never experienced this before. The engine is the 2 AZ-FE (4 cylinder) toyota in a 2008 Scion XB. There is no check engine light on.