So as the title states, I get a strong burnt oil/exhaust smell in the cabin after boosting my '91 940 turbo sedan.

At one point, I could see the fumes when the light hit them the right way in front my me.

The exhaust does only has a small leak but in front of the rear most muffler. Is there a good way to check to see if the exhaust manifold has cracks (as I know they're common) without taking it off? (This seems to be the most likely culprit).

Also, I've read about the cowl/hood seal not sealing properly, but mine seems ok, it dips down a little at the passenger side, but I doubt that would be enough for fumes to flow in that heavily.