The dealer said the failure was due to a lack of oil causing (2qts low) the #4 cylinder rod to wearing, not sure on what, and created metal filings which clogged the filter to the turbo which the starved the turbo of oil. No warning, car ran fine up to the point that it didn't. I don't know when or how the oil was lost. It seems to me that an engine that has been maintained should be able too, under normal condition, survive a low oil condition without metal to metal wear.