I have been driving my beetle with the check engine light on for a few weeks up until today when I got it checked by auto zone. They said it was spark plugs. My fluid light has also been coming on when I go over 40 mph. Today I took a thirty minute drive and on the way there the car was perfectly fine, on the way back it was fine as well. When I parked and turned off the car smoke was coming from the hood and I heard a gurgling. I opened the hood and the blue nob(on the right side)(antifreeze I'm guessing) was popped open and leaking and it leaked through the bottom of my car. Any ideas on what this might be and how much repairs would be?