Thank You for welcoming us to the Forum. The last week my son has had the issue with AC Blowing out of the dash vents, and knew it was a vacuum leak and it was on our list of repairs. Today my son returned from an oil change where they changed oil, filter and topped off the coolant. He drove home about 5 miles, turned off the car and went inside. 10 mins later neighbor calls said they heard a loud noise and white smoke. We open up the hood to see that the two main lines going thru the firewall have come clean out. What in the world would cause this? Thank You!