2004 X5 4.4 85K white smoke

[manfrmbklyn23]

After idleing for more than a minute or two, at take off I am getting one big cloud of white smoke but, it quickly clears up. four months ago I had the same problem and the dealer repaired both crank case vent valves and covers. They also replaced the head gasket ($3,000) The smoke is back and now the dealer is saying that they must repair the "valves stem seals" they didn't run any test and basically are basing this off of experience ($5,000). Why the heck didn't they find this 4 months ago? I am SICK right now! Car has been nothing but trouble since day one. Any advice or suggestions would be greatly appreciated. I don't know if I should fix it with a non dealer shop. In fact I have no clue where to bring a BMW for repair in NY other than my dealer. Is it worth it to fix this car? Should I just keep replenishing the oil and drive it until it dies? Will it die? Thanks in advance for any help you folks can offer me.