One problem related to diesel engine has been reported for the 2007 Chevrolet HHR. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2007 Chevrolet HHR based on all problems reported for the 2007 HHR.
2007 Chevrolet Hhr had a catastrophic engine problem. The master cylinder was not supplying combustion to the third valve of the four valve engine. Which meant no remote control start, it sounded like a diesel engine and the gas mileage had dropped from 32 to 24 miles per gallon.