Overheating???

May have air in system try bleeding air from system like this remove cap from over flow tank fill with antifreeze to full mark leave cap off and start vehicle and let idle you will notice level in tank start to rise this is normal once thermostat starts to open level in tank will drop add more antifreeze to full mark then put cap back on.

I'm having same issue with my 2009 hhr ss new fan new thermostat :( I'm getting 220 - 235

Temperature sensor next checking for bubble & blockage at dealer tomarrow . Has anyone upgraded the radiator?

Fan relay module that is attached to fan shroud. It will also effect the A/C system

On an HHR SS, the cooling fan is controlled by a fan module mounted on the rear of the radiator. There is no #51 cooling fan relay in an HHR SS, the fan module controls the speed of the cooling fan. In my HHR SS, I have had to replace the cooling fan when the bearings seized up due to no lubrication. The dealer had the car 3 times and could not make the fan fail and overheat the car. I let the car idle in my garage and found out in 27 minutes what the problem was. The dealer drove the car to test it, and the ram air going through the radiator started up the cooling fan and the mechanic could not get it to fail. I found out what the problem was by letting the car idle. With no ram air coming through the fan blades, the fan motor did not start up and the car overheated. I nudged the fan when it started to overheat, and the fan motor started up and cooled the engine down. The bearings being dry would not let the motor armature turn, so no cooling and the engine overheated. After replacing the fan module at my own expense I took apart the old motor and replaced the motor bearings. I put high temp Mobil 1 grease in the new bearings and now I have a spare fan motor when mine fails again. It was amazing that the GM mechanic could not replicate the problem, and me not being a "qualified mechanic" the extended warranty people didn't want to reimburse me for the cost of the new cooling fan assembly that I bought and installed myself. I cancelled the balance of my extended warranty, and now have a spare fan motor with better lubricant in the motor bearings than the original GM cooling fan assembly. When my present cooling fan assembly fails, I will just swap out the rebuilt fan motor, and I expect that it will last longer than the Delco GM fan assembly I put in last year.