One problem related to crankcase (pcv) has been reported for the 2006 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Toyota Sienna based on all problems reported for the 2006 Sienna.
One of the front engine oil seals failed while the vehicle was being driven in local traffic causing all of the engine oil to be pumped out onto the hot engine and exhaust emptying the crankcase in little more than 1 minute. I pulled into a gas station and opened the hood to investigate the smoke and smell of burning oil. The oil on the hot exhaust ignited and was quickly extinguished with the stations garden hose.