I have a 2006 hhr lt. with the 2.4 motor that I bought in 2008 with 89000 miles and it runs and drives great and I changed all the suspension a year ago ''' my problem now is my temp gauge quit working and I bought a new temp sensor'''' which I have not put in yet as some say it's my thermostat which I changed so that is not the problem and the heater works great and it is not overheating as I just took a 100 mile round trip with no problem ''' also I just filled up my coolant tank which was low ''' I am going to have the codes cleared tomorrow and see if anything changes'''' also where is the coolant temp sensor located on the block ? thank's for any help you guy's or gal's can give me''''

 

Welcome

"Codes cleared tomorrow and see if anything changes"
Sorry, but I don't think you understand how the OBD system and codes work.
Codes, or trouble codes just tell you what part of the monitoring system has detected a problem.
Clearing a code won't fix anything.

If you're looking for some diagnostic help then post up the code numbers. No descriptions of the code because sometimes they are inaccurate.

 

Welcome to the site, first off...
What thermostat did you install? It’s a well documented fact that anything but an AC Delco 131-158 will not satisfy the ECM in its opening time, and throw a P0128 code.
Second,
If you did not use Dexcool and did not flush it all out before you poured in go old Green coolant, well , it’s well documented the two shouldn’t ever be mixed!!
Third,
If you changed the thermostat and the Dexcool, but didn’t burp the cooling system, air trapped in the system will cause nasty problems.
If you are going to get the codes cleared, take the time to write them down, just the codes, post them up and we’ll go from there.

 

Ding ding ding ding!!!! I fought that battle with the air in the system and 7 coolant temp sensors. ._. Rent or purchase the Snap-On RADKITPLUSA cooling system vacuum/filler and be done with it.

 

I just recommend the park it nose high overnight method , no fancy equipment to purchase or store. Just common sense

 

X2
Those of us that have been on this forum for many years have taught and learned about our little trucklets.
I've even used the nose high method on other vehicles in my 40 years of wrenching on cars.
Yep. No real need to recommend fancy equipment.

 

Yeah, I tried that method. Maybe I just have the bastard child of HHR's. I placed the car front end on jack stands and left it for two days just to be safe, filled and verified the coolant level, squeezed hoses, and stil had the temperature sensor disabling itself. That tool saved me a lot of time, took a max of 30 minutes and you are also able to test for leakes with it once you pull that vacuum!

Interesting thing though... When the coolant temperature sensor stops registering on the dash (The ---) the ECM was still displaying the temperature on my Tech 2. O_o Really cannot find a theory of operation on the cooling system for the HHR, but when it stops registering on the dash, it disables the A/C compressor from kicking on (which is understandable), but if the ECM can still register the coolant temperature, why on earth would the A/C Compressor and the dash gauge be disabled???

 

Dash gauge disabled was just an odd way that the GM engineering gurus programmed it. Guess they thought it was a way for the owner to see that something was wrong and would get it checked out.

AC shuts down because that system shares it's cooling system with the cars engine cooling system. (same fan for radiator/condenser)
Again, guess those gurus figured if the engine cooling system ain't working right, then the AC system (condenser ) may not cool correctly. Shuts it down to prevent any damage.

 

Well... thinking about it, I guess it isn't a bad idea.

 

The --- and the A/C when you have a P0128 is GM's way of getting your attention. So many people ignore the CEL that they add other things that you can't ignore.