Cummins and Valvoline worked on this as a last-ditch measure before a rebuild for the ISX engine which is a 12/15L engine but totally different as the 12L ISX/X12 is a OHV engine and the affected engines were the OHC 15L version. Per Cummins, you need 4 cases of VPBR to do a service on a ISX, 3 to do the oil change and 1 for top off during the 10-12K OCI.
Originally Posted by maxdustington
It was originally designed to clean the rings of Cummins ISBs I believe. A bunch of them started getting sludged rings so Valvoline created a mega cleaning oil as an alternative to replacing the piston rings that is approved by Cummins. OP's engine is obviously not the intended purpose but VPBR is an oil designed for cleaning, not just an oil that has cleaning properties as a byproduct of it's formulation like Redline or other group 4 and 5 synthetics.
Originally Posted by kschachn
That Valvoline Premium Blue Restore is marketed to semi truck engines, right? Do they typically look this bad when needing to use the product?