help please my car has developed the leak the smoke coming off is entering the cabin and is really bad I removed the under side covers yesterday and noticed the cat was covered in well its like a fine oil clear but no smell from it. There is no leaks further up the joint and the pipe is dry . The car is running perfect no loss of power or light on the dash. just wanted your opinion on this please its the oil substance that's got me baffled or is this just some unspent fuel >