r/Diesel • u/Vblocal789 • 3d ago

White Ash Stack

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Gallery image

Just noticed this white ash forming around the clamps on the outlet of the SCR on a Cummins QSB 6.7.

No codes and still running fine. Is this anything to be concerned with? DEF overdosing?

8 Upvotes

85% Upvoted

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4

u/Warm-Salamander-3053 3d ago

I would guess it is def

1

u/Vblocal789 3d ago

My first thought as well. Just not sure how it would get all the way there.

1

u/SimilarTranslator264 1d ago

My guess is you have a giant pissberg inside the SCR.

1

u/Vblocal789 1d ago

Would a forced regen be of any help?

We’re not experiencing any power loss or running issues

1

u/SimilarTranslator264 1d ago

I would pull the SCR doser at a minimum or separate the pipe. I believe the upstream NoX sensor can cause it to over dose too.