donbrew

Sounds like it's fixed, they probably had a bad algorithm in the program. Mine "usually" is 185F. sometimes 230F. The analog on the dashboard is probably more important to humanz, just below the halfway hash mark (which is 2/3 of the way up).

ChevyGirl

I had the same problem with the thermostat last week. I also noticed there was no coolant in the engine, which I thought was strange as I dont see any leaks. So I replaced the thermostat and filled the coolant. After pressure testing the system, there are no leaks. Would the bad o-ring account for the loss of coolant or do I need to start looking for leaking in the head gasket?

donbrew

Head gasket should be easy diagnosis, do you smell hot coolant, are the spark plugs (outside the engine) a funny color, is the oil a funny color/consistency filling itself up? Coolant does evaporate, and we have become too lazy to check the level regularly.

Double take

Geez what a helpfull site, THANKS ALL - here go's...Eng temp sensor showing no reading -0°- nada....With help from site, No sensor readings, check fluid! go figure, way low...added lots....sensor working again! Makes sense, sensor needs some thing to sense! Ha Ha?! Happy 2012 all!!!

jlwalter

my 2007 hhr temp gauge didn't work and temp reading was "---". Then a while latter, it does work. Finally I took it to mechanic and he thought it was sensor. which he replaced. worked fine for a week, then didn\t work , again intermittently. Left it with him again yesterday

donbrew

Did anyone consider the t-stat?

whopper

x2 - and if it is the thermostat that has jammed open, making it slow to warm up, the temp gauges will blank out periodically when it does not reach an appropriate temperature after being started from cold. It is not necessarily due to low coolant or a bad temp sensor.

If you find that the gauges work after restarting the car once it is warm, and has sat for a few minutes, definitely suspect the thermostat.

oldracer

I think I mentioned in my post about the same issue with my 2007 2.4L that I decided to replace both. Since I am an older sort of guy and had just gotten over some total heart bypass surgery I only wanted to dive into that little hole once.

I have found over the 49 years I have been working on my own cars that if several possible things can cause a problem.....fix them all at one time since as per Murphy's law.....you will probable miss the one that is actually causing the issue!

handlebaron

I have a 2010 hhr , the temperature sensor works some times. Can I change the sensor without a lot of mechanical knowledge? where is the sensor located?

whopper

A quick search on Google: | Repair Guides | Coolant Temperature Sensor | Removal & Installation | AutoZone.com

But what makes you think it is the sensor itself? It is more common for the thermostat to cause a problem, like the details above in this thread.