One problem related to engine cooling system 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.
Driving my 2006 Toyota Sienna on a busy freeway with three children ages 1, 7, & 10 when the air condition compressor decided to seize up causing the belt to burn and eventually snap. The burning belt resulted in a little smoke and a fearful smell filling the cabin. Fearing a fire, I was forced to pull off the road putting myself and my three children in harms way. After determining there was not a fire, we climbed back in the van and continued on our way. After a little research, I've learned the compressor problems are not uncommon in Toyota Sienna. In my case our vehicle had less than 45k miles. Seems there are many unsatisfied Sienna owners who have experienced a similar problem, and Toyota should consider recalling all vehicles with this air conditioning system. I feel this is a major safety concern since the Mini-van is considered a family vehicle.