smoking engine. help!!

[navy17]

i changed the air filter in my 92 today, and when i was driving it around right after my engine got hot as hell and started to smoke, i opened the hood up and the smoke was coming out of the back left of the engine towards the bottom. i dropped a bolt in that area a while ago but i dont know if that is whats causing it and why it waited till now to do it? any suggestions on what it could be?

 

[navy17]

i also added a quart of oil, but i do that about every month because it burns a little oil

 

[ld50]

You may have spilled something on your exhaust manifold; any chance you spilled a little oil? Could something have fallen back there?