Diesel Fuel On The 2004 6.6 Duramax Engine Oil

[RXTII]

My car is having some diesel fuel contamination on the engines oil, this is happening after refreshing the engine with new pistons rings, valve seals and rod bearings, any ideas why this is happening? I am guessing this is why it is also stalling after 5 minutes or so of revving the engine at 2500 rpms.

[DmaxMaverick]

Sounds like you have a fuel return line leak. On the LB7 (early 2004), the return pipes are under the valve cover. Could be either a poor connection, or a cracked line or connector.