Leaking Common Rail Pressure Relief Valve

[Richard Tree]

Has anyone had a problem with the common rail pressure relief valve
leaking on the 5.9 and 6.7 ISB?  I noticed a small wet spot at the top
of the boss where the valve threads into the common rail.  This
part number is normally a Cummins 3947799 (per ESN) and is rated
I have read at 27000psi.   The Bosch number is 1110010029.  Any insight here?
There seem to be lots of sources for  new valve (Maybe worn) and some
knockoffs for the RAM crowd.  COLA shows a $500 price?

Thanks!