One problem related to engine burning oil has been reported for the 2005 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2005 Toyota Sienna based on all problems reported for the 2005 Sienna.
I was driving home from work, after merge from rte 20 into rte 9, I drove up hill, about 50 yards to my street, I saw smoke behide my van, I did not see any warning light from my driving panel, my van was still running smoothly, so I decided to drive to my house (about 150 yards) away, after I parked my van, I saw smoke coming out from hood, and a long leaking oil track along the street. I checked my engine oil, it was ok. Next morning, I started my van, it is still no warning light on my driving panel, I called aaa to get my van towed to Toyota westborough MA. Technician told me that my engine cylinder head got blown a hole and oil flying out to be burned and produced smoke, potentially it will catch fire if I continue to drive. I had my van oil changed on 08/2012 by sears shop, about 5,000 miles was driven since last oil changed. I believe the engine aluminum head was defective product, not because of other reason. It is very dangerous it happened while the van was running at highway. It could catch fire too.