Today after driving home, I opened the hood with the engine still running. I removed the small rubber hose (one leading into the firewall) from the metal tube on the check valve. And here is what I found out. To test if the check valve was clogged, I placed my finger on the opening of the metal tube expecting to feel air blowing out. Instead, the check valve sucks in air. I placed a thin tissue in front of it to double check. The tissue stuck to the metal tube like what a towel would do on a vacuum cleaner hose. Does this mean my check valve is not clogged? I somehow thought that it would blow air out of the tube...and into the rubber hose and into the dash. Is my check valve functioning properly?