We just traded our Sienna in after 1 year and 37,000 miles. For those who are not yest aware, there is an congenital engine defect in some Siennas that causes the engine to sludge up after low mileage, even with documented oil changes. It has to do with valve seals and the temperature of the engine. The Toyota corporate position is to deny all warranty claims and there are several class action lawsuits in progress from unhappy owners like ourselves. You can find out info about the problem, and the suits, on the Edmunds car site or the complaintstation.com. It was a wonderful family car before we became victims problem but now we are very happy with our new Honda Odyssey.
