 Purchased a new 2001 Sienna XLE in 2000. 3 years later we had to replace the engine due to oil sludge. Toyota calls it "oil gel". Toyota fought us at first but then agreed to fix the car when we produced oil change receipts.  2 years after that the engine started leaking oil, and we had to replace all the oil seals.  Again we had to fight Toyota for reimbursement.  Also around this time we incurred over $1800 in costs to replace various fuel and exhaust sensors.  And even after that, the check engine light kept coming on.  Finally after another 2 years (we had the car 7 years and 80k miles at this point), and a major oil-related repair bill, the engine seized again from oil gel build-up. Avoid the Sienna.  We junked the car after spending thousands on oil sludge related repairs and two engine seizures.  A total nightmare.