The most common leaks on the 6.0 are as follows in descending order of occurance: (Notice the First four items comprise 65% of all reported leaks and are a simple fix.)

CAC Tubes = 21%
ICP Sensor = 16%
Glow Plug Harness = 14%
Cam/Crank Position Sensor =14%
Front Crankshaft Seal = 8%
Upper to lower block seal (skirt) = 5%
HPOP cover = 4%
Oil Cooler (this leaks into engine coolant) = 4%
Front or Rear Engine Cover = 3%
Rear Crank Seal = 3%
Turbo Charger & VGT actuator = 2%
Covers (oil pan, valve covers, breather) = 2%
Cracked or Porous Block or Head = 1%
IPR valve/Engine Lube oil pump = <1%

Oil Leak from Rear of Engine Area:
< Oil leaks from the rear of the engine should be indentified and pinpointed using flourescent dye and an UV lamp. Leaks from the top of the engine can run down the back of the engine appearing as rear main seal leaks (check for upper engine leaks first; Braodcast Message 499. Oil from failed cam or crank sensor o-rings can run along the seam between the main block and bedplate (lower cranckase) joint, apperaing as rear main seal, bedplate, rear engine cover, or upper or lower pan gasket leaks. Cam and crank senaor o-rings are available separately from the sensors (see msg 1268 below). Oil leaks can be cause by removing the front or rear engine covers without first cutting the gasket at the cover/block/bedplate joint, or failure to seal this joint with silicone on assembly. Broadcast Message 5164.

2003-2004 Oil Leak from Head Gasket:
Some engine may exhibit what appears to be an oil leak from the head gasket. Since there is no pressurised oil at the head gasket, a leak at this location is unlikely. Inspect the following area instead: turbo oil feed and return, oil cooler, HP oil pump cover, ICP sensor, IPR valve, valve cover gasket, rocket carrier gasket, Injector and glow plug ports and crankcase breather port. Use florescent dye and an UV lamp to pinpoint the source of the leak. If the leak is from the head gasket, the head should be removed and it and the block checked for flatness. Broadcast Message 0873.