2010 chevy 6.2 @ 166k miles cylinder 5 lifter failure.
Have serviced engine @ 30% oil life nominally 4k miles with full synthetic oil since new.
Lifter roller failed. Roller contact surface pitted, destroyed. Bearings still ok. Cam destroyed.
This replacement requires cam, heads remove& replace, front differental,for pan access to oilpump, to replace cam.
The engine was clean as new inside. Ive driven since new.
Clearly a part problem, 1 failed lifter cost $7,000.
Way too early 166k for a 6.2 motor to fail.