2012 Isx 2350 475 with codes 4726 and 0559

[Rawze]

(01-25-2022 )ahrenbenjudah Wrote:  ...
Following the Cummins test of blowing air in to the inlet of the head, the plungers both extend. But as soon as I remove air, the rear one sinks back in to the barrel.
...

did you ever fix this problem,?.. those plungers are NOT supposed to sink back down.. not one bit... but spring back and stay up.. indicating they are not leaky.

also, if the guts have more than 8,000 hours on them or 400k miles of use (or if you really donl't know how old they are).. then all the guts (tappets, plungers, barrels, etc.) need replacing to prevent complete engine destruction.