I don't know if this will help but before my last oil change i used this stuff with the brand name of "Gunk"(or something like that). I t helps get rid of the petrolium byproducts(varnishes,sludge,etc) that build up in your system. What i did was pour it in to the crankcase right before i was about to change my oil. Then you let the car run for like five minutes and then you change your oil. Now what I noticed when i got under the car to change the was kinda cool. When I started to drain my oil it came out in two different colors. There was the normal oil after 3000 miles color and there was a really dark color.
In my opinion i think the stuff helps to clean things out at least when it comes to the lubricatrion system. I am not sure if that will help get rid of the smell but it might help and it definatly could not hurt.
ronin