Today I drove my 2000 Subaru Outback in hot weather with the A/C on for about 15 minutes. I got back home and pulled into my driveway. I stopped the engine and within a minute, restarted so I could pull the car forward. As I started, I heard a small explosion under my hood and saw a bit of smoke coming out the sides. My engine then started sounding like a truck/tractor. I looked under the hood and I dont see any loose belts, hoses etc. Also, today is Sunday and I cant get it to a mechanic. I tried starting the car after things cooled down a bit and it still sounds the same. As I give it gas, the engine rattling/awful noise just seems to get louder.
Any ideas on what happened?