2004 chevrolet aveo head gasket blown?

[I love my wife and kids]

there is oil on top of the piston and when i pulled the plugs they looked as if there was some water but mostly oil and its blowing white smoke but oil is not milky looking and no oil in water that i can tell and it only blows smoke right after start up after sitting a while but when running no smoke and no loss of power but has been burning more gas than usual so do i have a blown head gasket and do you think it is covered under my 7 yr 100,000 mile warranty that i got through gm when i purchased the vehicle and it only has 40,000 miles on it


the dealer service department says it is the valve cover gasket what do you think i dont believe them i would think that the valve cover gasket would cause a leak to the exterior and smoke from the engine block

[tummybulge]

the valve cover gasket is quite a common problem , also the valve guide seals get toasted after awhile and they will allow oil into the combustion chamber too.