Thanks for the help! The dealership says the warranty for this issue is 6yrs or 60k miles, both of which I exceed. They did however revise their price to $3900 and it includes a rear engine seal. They also said they would replace the valve cover gasket and only charge me for the parts. The next time I talk to them I'll see if they can make a case for me with Lexus corporate to pay for a portion of the repair like your case. Thanks again.