my boy just found oil in his muffler but cars running fine, any ideas?

 

Sure its oil? Your exhaust pipe gets carbon build-up in it. Which is totally normal for an internal combustion gasoline engine. As your exhaust pipe cools down moisture builds up in it. Then when you start it and the pipe warms up you see the water turn to steam(thats what you see when its cold outside in the winter),what it might be is moisture build-up in your muffler which is water turning black from the carbon. Is it burning any oil? See any BLUE smoke from the exhaust pipe?

 

i havnt seen it yet, but he said their oil inside the muffler, i thought carbon builtup also but he said its shinny