My car has been running at or around 180 since I purchased it in Aug. Well this morning on my way to work I was using the heater and noticed that I was running at 195 on my DIC. I adjusted the temp control all the way to cool and it went down to 180 after a minute or two. As soon as I went back to heat, the temp rose up to 190. I arrived at work before it got any hotter. The whole time I never had my a/c on. I had almost forgot about it on my way home, at this time I was just using the vent to keep me cool as it was 55* outside. It was running at 180 again but I then turned my heat on to see what would happen. Sure enough it ran all the way up to 197 then backed off and stayed at 194-195. Is this something to be concerned with? It goes against everything I thought I knew about cars, ie if it starts to overheat to turn on the heater to remove excess heat from the cooling system.

 

I believe the thermostat opens at 180. Our 2.2 runs between 187 - 190.

195 isn't going to hurt anything.

I am kinda thinking 180 is a little cool and may affect your gas mileage.

 

Start listening for what would sound like a "Waterfall or rushing water" in the dash upon cold start up and moving. Would indicate your low on coolant. Also you should start smelling a faint smell in the engine bay or when the car is running.

Common issue is the Thermostat, and since mine is a 2007 w/o any coolant service and is at around 31k I am doing a flush and fill this weekend, also been mention to do a little over fill on the system to ensure no air. Check the Problem / Service Section.

https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/

 

Yeah if anything 180 is running almost too cool like the thermostat is stuck open, it may not be though, and this is just a quirk of your particular vehicle. 195 is not running hot by any means in an HHR, I normally see 188-194 on all three of ours even on the hottest Carolina summer afternoons.

 

On a side note before I forget. Mine is low, and my idling coolant temp has been peaking just over 220 which for MOST GM's seem to be normal but with what my HHR has seen has never been over 200 on the DIC.

 

First things first how about checking the coolant in rad. when eng. in cold to see if low !

 

The HHR's thermostat opens at 195 degrees, as do modern cars. Anywhere between that and probably 225 is normal. It's when you get 250-260 that concerns start popping up.

 

What he said!

 

Normal operating temp up until today was at or around 180. 'I would see it get to about 185 or 186 then drop to about 179. I was thinking that's when the thermostat opened up and cooler water entered the engine. I do recall smelling something sweet a few times on my way home. I'll go and check out the coolant level later, as I have been driving it a little bit. My car is a 2010 with a 2.2 engine. 25450 miles

 

I checked the coolant level first thing this morning and all is good. I drove it the dreaded Wal-Mart for groceries. Outside temp is 55. I turned down my radio and drove it to the Interstate that is 1.5 miles down the road. A/C off and climate control all the way to cool. (Yeah I know probably messed up there.) Never heard or smelled anything out of the ordinary. Coolant reached 181 then drops down to 175 for the first 4 miles on the Interstate doing 70mph. This time its running cooler than normal. I turned the heat on to see if I could get it to repeat yesterday's events. It gets up to 185, then drops back down to around 180 with heat on. I can then get it down to 175 just by turning the climate control to cool again. Like I said in my first post, its doing the opposite than it supposed to do with heat on, ie cool off the water temp. I know a thermostat stuck open would cause lower temps, but will it cause my temps to go up when using the heater? I can change it if I have to. As for my daily driving and route, its about 5 miles of 70mph, 10 miles of 55mph and then about 5 miles at 45. I have one stop at a red light usually on my way home (same route reversed). Average speed is 46mph. Average mpg is 27 to 28. I don't dog the engine.