Coming home from the va clinic I noticed my engine temp guage bottomed out not working and the digital showing …F. My check engine light was on. Car was not overheating, was running great for a 2007 , 46000 original miles on it. Last summer the dealer serviced the ac coolant and replaced the thermostat at my request. They also replaced the fitting causing my loss of ac coolant. No problems till now. My ac is working fine, we still use it here in florida. Am I looking at a temp engine sensor? Would rather do the work myselk. Thanks for the info.

 

Find out why the check engine light is on. Most auto parts stores will read them for free, get the NUMBER and post it here.
Usually it will be P0128, that means the t-stat failed because the dealer installed the wrong one 131-158 is the ONLY correct one. But that turns the AC off so it may be something else.

 

Thermostat, trust us , it must be an AC Delco 131-158 180 degree thermostat. Make sure the coolant is Dexcool 50/50 mix. And ensure it is burped properly.

 

Just found my code reader, put it on the car and guess what…. Po128, just like you said. Thermostat. Ordered one on amazon, acdelco. 131-158, 180 degree. Checked my repair bill from august 2020 so the gm one lasted 14 months. I rechecked my ac and it was not working so that is why I dug out the reader after your help. Was pretty cold here this morning and did not use the ac coming home. All I can saynis thanks.

 

That code shuts off the AC and cruise control. You got 14 months out of their GM or AC Delco professional grade $15.00 thermostat!
Thankfully it’s easy to change!

https://www.chevyhhr.net/forums/how-...l-p0128-24493/

And burp!

https://www.chevyhhr.net/forums/how-...-system-60614/

I have changed the thermostat without removing the rad cap, didn’t loose to much coolant, into the catch pan I placed under the HHR . I still burped the coolant afterwards.

 

There is a small possibility that the temp sensor is bad.

 

Yes that’s true.

 

I replaced the thermostat with the proper ac delco one. Took longer to find a dropped bolt than the actual replacement. Reset the codes and things work as they should. Thanks for the online help.

 

To bad we can’t get our hands dirty from here! Glad it’s fixed! Just check the coolant every morning before start up to burp any air out of the cooling system. And park front bumper high if possible!

 

I had the same no temp gauge ---F reading going on. Honestly thought y'all may have been a bit nuts to think the thermostat would fix a temp read out, but changed the thermostat anyway (found part of the gasket stuck in the 'old' thermostat, not allowing it to close)....voila I gots temp readings again!!! So, I asks myself, WHY did allowing water to flow and not to flow fix the temp readout?