Oil in airfilter and in airbox

Take it back to him and leave it for him to sort it out

blown head gasket --cracked head --or damaged engine block blue smoke is oil being burnt and the milky gunk is coolant/water mixing in with the oil

is the smoke coming from under the car or out the exaust pipe?
under the car ! you have an oil leak and its probably landing on your exhaust pipe which by the way can ignite and go on fire if the pipe gets too hot. if its out the exaust ! computer or air intact problems. worst case: rings are bad and oil is mixing with the gas in the piston chamber. Hope this helps a little good luck and God Bless

Is it smoking all the time or just when your driving? It could be burning oil or you might have a upper head problem which will leak oil and cause it to smoke.

blue smoke is oil
black smoke is fuel
white smoke is coolant
sounds like head gasket if you are lucky
head cracked if not lucky

check your exaust first to see if there any holes that is could be coming out of and going into the shifter and if there arent any you may have a gasket leaking throughing oil onto your exaust causing the smoke

Exhaust smoke is not a good thing, it can slowly destroy the catalytic converter. The color of the smoke is important to know, gray smoke is usually oil burning and white smoke is coolant.

the tapping is probably from low oil level,you need to keep it full untill you repair the oil leak

Replace the head gasket.

usaually white smoke means you're burning too much oil.