Just changed my thermostat and filled the coolant system with antifreeze and water 50/50/. It is 42 degrees at at the time this happened. Started the car to cycle the coolant through the block so no water pockets would freeze tonight. When i started it there was a very loud bang, thought my friend hand slammed my hood from sitting in the drivers seat so i immediately killed it. He said when i started it a cloud of smoke came from my plenum cover, i guess where the seal is. I started it back up for a second and it sounded like something was knocking but had a rattle type of sound, immediately killed it after hearing that. Also the car had run out of gas prior to this, i had just put a bit over a gallon in it before started it up, did let the fuel system prime before starting. am i fcked????
