One problem related to engine head gasket failure has been reported for the 2011 Chevrolet HHR. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2011 Chevrolet HHR based on all problems reported for the 2011 HHR.
Never received any warnings that all of the engine cylinders were cracked with the exception of the temperature going into cooling mode one time. Took in for an oil change and asked them to check it out while it was there. Entire engine needed repaired at 50,547 miles. All cylinder sleeves cracked, replaced head gasket, head intake and all seals, gaskets and o-rings.