I have a 2009 chevy hhr. The car does not overheat, coolant temp. is always 180 - 190 degrees. Coolant levels are good, water pump is working fine. Blower motor is working good. I just can't get any heat inside the car. Both hoses that connect to the heater core get hot and it does seem like the car warms up faster then it should. The car will sit for 10 hours on a cool night but before I leave the parking lot(with very little idling time) the gauge is already 1/4 of the way up but it always stops at about 1/3 and the car doesn't overheat. Coolant temp ranges between 180 to 190.. somebody help. I don't think it's the heater core but I don't know and I don't want to start replacing parts that aren't necessary.

 

Is this new behavior? Are the controls set properly?

My guess is the blend door is stuck on cool.

 

Welcome to the site! Any air in the coolant system? Park your HHR nose higher than the rear, let it cool off and open the rad hose cap, there should be coolant there not air.