Has anyone experienced engine failures with the 8.1 vortec? I have a 2004 Winnebago and have had two engine failures, the first on with 17, 000 miles on it for a ring issue. And now a blown head gasket on the replaced engine with 7, 000 miles on it and they are telling the motor needs replaced again, this time out of warranty. Any feedback is greatly appreciated. Yes the unit has been maintained, and was in for service two weeks prior to the trip it broke down on.