So I have the pentastar in my new ram. And I also had the kinda fart smell when driving slow or stopped at a traffic light. Well I am happy to say that with around 7000kms I dont really notice the smell anymore
I ended up having to change my antifreeze on my own, note to self when you check your antifreeze, do make sure you put the radiator cap fully back on. That mistake cost me 100 bucks (antifreeze) 2 gallons from the dealer and they gave me a break and gave me wholesale. (full strenght you have to dilute and have to use distilled water.).
And mine has went away as well from doing that.