Hi, I have a 2003 Toyota camry LE, and just got my oil changed, including the airfilter. On driving back home, I heard a humming noise coming from engine. Any thoughts what this could be.
Harry

 

Did the put oil cap back on the engine? Is the dipstick in its tube? How about the air filter, maybe it is put in wrong, or its cover isnt secured properly. Since you werent there when the work was done, could be any number of things, maybe they knocked something loose.

I'd put on my detective hat and try to backtrack, that is, how would i change the oil and what kinds of mistakes could i make if i were a stupid, untrained, cro-magnon quicky lube employee? And just go from there!
Reason #1,233,334 to do your own oil changes. [:-]