2006 Toyota Highlander: What is the oil type and capacity?

The base engine the 2.4l for the 2006 Toyota Highlander useS4 quarts of 5w30 synthetic oil. The two versions of the 3.3l option take 5 quarts of 5w30 synthetic oil. Synthetic oil is by far better for performance. It protects the engine due to lower levels of friction. Switching between synthetic and conventional oils will not cause any damage to an engine. Synthetic blends are a mixture of synthetic and conventional oil. Synthetic oil keeps engines cleaner. When oil travels through the engine, it picks up debris and deposits from tiny fragments of dirt and tiny slivers of metal which damage engines.