Check with your dealer.I just read in the combine productivity guide that oil fumes in the cab may be from the forward gear case vent,and that the vent can be relocated.Good luck.
I never allowed the dealer to update my 2188. I'm sure happy the cab filter is still on the left side of the cab. I've never had much trouble plugging it there either and none of the issues with that thing over behind the right service door.
i have remounted the filter to the right hand side of the grain tank and run tube up to it. no more smell and the filter doesn't have to be cleaned daily. some people are using a cotton picker air cleanerr. haven't saw one done, but they mount behind grain tank.
there's a update for 2388 12 row ready combines to change the type grease. this will make it go away Mine did anyway the newer machines have a bigger gear case that hold more oil hope this helps