One problem related to engine head gasket leaking has been reported for the 2008 Toyota Yaris. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Toyota Yaris based on all problems reported for the 2008 Yaris.
During oil change I decided to look for any oil leaks and discovered oil down on the back of the engine to the oil pan. Dealership put dye in engine. Confirmed head gasket leak. Head gasket was replaced by dealer. That same day, I looked at our other vehicle same model different year 2010. I noticed the same oil leak. Since then, I have looked at three other 2010 Yaris and found the same oil leak from the #1 cylinder of the head cylinder gasket.