2013 international 4300 maxxforce dt smell

Hello I have a 2013 int 4300 with the twin turbo maxxforce dt engine. Its smells really bad at idle and low speed. I replaced exhaust manifold gasket which helped for a few months until it started smelling again. I had the dpf filter cleaned and that didn't help either. Any tips or ideas much appreciated

 

Its hard to describe. Its not coolant because its not losing any. It smells like exhaust fumes but when I try to smell outside I cant locate it but it will only smell in the cabin

 

Thanks will check for soot today, its possible for the egr cooler to leak exhaust gasses?