Funny I should find this thread today. I posted yesterday about having my transmission replaced on Monday in my 2000 RX300 (87k), and the oil pressure light coming on while driving home from the dealer. It was towed to Lexus this morning and the diagnosis came back that the engine now needs to be replaced because of oil sludge.
If I could provide oil change receipts for the last two years (which is how long we've owned it), Lexus would cover the cost of the new engine. So I produced the receipts. Finding this thread now makes everything they told us make sense. They never mentioned there were previous problems, just the part about receipts. We'll still be out $600-$1000 for other parts they will replace that would have been part of a 90k checkup. Things like the water pump, timing belt, some gaskets, fluids and a list that's about 20 items longer.
What a whirlwind couple of days this has been for us. You guys have been very insightful.
Thanks!
Suzan