lately ive been noticing an exhaust smell inside the cab, possibly through the air vents. through some thorough investigation, I found that there are two holes on the side of the turbo under the heat shield, that are empty (it lools like they might connect the two turbos). it seems there should be two fasteners in these holes. I was wondering if I could get others input on this issue, as im not 100% sure anything goes in these holes. *Note: still trying to figure out how to insert a picture. will post when I figure it out.

 

Nope, nothing goes in there. There are seals between each turbo, and the hold down bolts secure both in place.

 

Is there black soot around that area? If not, then likely its not the source of your in-cab smell. It may be likely you have a cracked up-pipe. Look on the underside of the hood and on the firewall behind the engine for soot...if there is, it's probably the up-pipe.

 

I didn't notice any soot on the heat shield, so I think I can rule the turbo out. I did however find some build up on the ends of the pipes go to the inter cooler, as if the hose clamps aren't tight enough. I tightened them up and the smell isn't as prevalent, but still existent. I will poke around under the hood this week for some further investigation of the down pipe. Thanks for the input.

 

My '08 still has the DPF and I get a noticeable exhaust smell when the regen starts. Unfortunately it regens quite often, so I will be doing the DPF/CAT delete and tuner very soon.