Oil smell

I have noticed an oil smell coming fron the front of my engine, when I look under the hood I see nothing.
Also there are no oil leaks on the ground or around the engine, checked the oil itself, and it is not dark or bubbly.
I did have trouble with my tail pipe, wondering if that had anything to do with the smell.
Anyone have any ideas, would be very thankful.
One more thing it is a 94 cougar, and does anyone know a good way to clean the engine compartment, without messing anything up?.
Again thanks for any and all help.