So I don't have a problem, I did a little experiment I've been meaning to do for a while.
I always wondered how smoke could come out of the exhaust pipe with the DPF there... designed to stop smoke.

I dumped about 1/2 of a pop bottle of diesel fuel into the DPF, bolted it on, and went for a rip. The fuel must be able to soak through the DPF and burn on the other side, because it smokes like a SOB.
And my tailpipe is super clean, like pure metal, not even grey like some guys.

So the point of all this, was to prove that just cause theres smoke, doesn't mean the DPF is cracked or broken. I also suspect hot oil would maybe also seech through the DPF and smoke, without any cracks etc.

 

An overfueling condition and a leaking EGR cooler would do the same thing...regardless of DPF status.

So yup...I agree.

 

The DPF will filter out particulate matter, but not fuel fumes like dumping lighter fluid on hot coals--though both look like smoke. But, the DPF has a washcoat of some precious metals that's supposed to deal with some of the CO, NOx and HC's that does make it across.

 

That precious metal is platinum.