William: It wasn't difficult at all because mine was a Certified vehicle. Is yours? If so, they shouldn't give you any crap about it. I've also read that even without the complete service history and proof of oil changes, Toyota (Lexus) will usually still replace/clean the engine. I wasn't able to see the history of my vehicle and I really didn't care that much since it was Certified. And I didn't actually get a BRAND NEW engine, just a new head, new oil pump, new seals and gaskets and a couple of other new items that I can't remember since I don't have the service bill nearby. They completely and thoroughly cleaned the other parts. In fact, the oil looks like real light-colored honey on the stick; much lighter than if it had gone into a dirty engine. The tech told me that the engine is as good as new because it's actually already broken in. The problem would only return, he said, if I failed to maintain it as recommended. Toyota supposedly redesigned the engine in 2001; I've got to believe that the new head I've got is of THAT design, which lets the oil drain back down faster. Good luck with yours.