Very strange smell. Stumped

[Grumpyjoewv]

i wouldnt have known how bad the box was if my blower motor hadnt died. when i pulled the lid off it had chunks of rust fall off it. i replaced the egr gasket and put on a new v band clamp. having a hard time getting it to seal with the manifold.i also noticed the manifold bolts were reused during the in-frame. manifold itself looks to be fairly old. gonna take it somewhere today and get everything checked for leaks