Logical or not, it’s the thermostat!
Please , ensure you install an AC Delco 131-158
the other aftermarket ones doesn’t open with in the parameters the computer is looking for.

 

Hmm. Ought to go right past that temp during initial warm up. Should get to about a 185-190 F reading, then drop to 181-183 when the thermostat opens. Then quickly back up to the 185-190 which is the normal operating range. (yes, some HHR's do hit higher temps which may be acceptable but any time it operates below 181 it usually indicates a stuck open thermostat.)

Try a thermostat as the others suggest. Many posts over the years about quirky temp problems in HHR's. Almost every one winds up being the thermostat. Easy and cheap repair plus you can change out the Dexcool which only has a 5 year life span.
AND. Only the AC Delco brand thermostat. Many folks on this forum found that "off" brands just don't work within parameters.

 

Another SS owner , confirming our diagnosis

 

WHAT the ..............?
Just read the OP's bio. Says the car is a COBALT. Now why didn't they mention this before ?
Yeah, I know they share the same platform but this is the HHR site.

 

Good morning firemangeorge,

I have no issue replacing the thermostat as it is relatively easy to do and a good precaution anyways, though at this warmer time of year I never see lower than 185F after reaching normal temps, which seems reasonable. When said I saw a min of 179F in operation this might have been twice, very windy cold -10F weather over the last two years. I can coast the car in neutral in the open wind and the temp never takes a nose dive below that (according to the coolant temp sensor anyway).

The absence of ISS occurs as soon as the vehicle is started and suddenly appears later, which seems to lock up the TCM's operation of the Pressure Solenoid Duty Cycle. It is like the sudden instant appearance of a value of say 1300 rpm from a 0 reading, while in motion is not handled correctly. The absence during start up of ISS just baffles me, and I am wondering if anyone else with a scantool has ever experienced this. One expects an engine to start off cold and gradually warm up - during that process the system should not misbehave.

If anyone is interested I could post a video of the log I ran on the vehicle.

Sewie

 

Keep guessing, we understand your problem, we’ll wait till you change the thermostat and test it out .

 

X2.

Why do we let clowns like this string us along? The person obviously isnt listening to the good advice and apparently doesn't even have an HHR.

 

Same thing with the hard/delayed/banging up-shifting 1-2, 2-3, and also Park or Neutral to Drive started about 2 years ago around 90,000 miles on my 2010 one-owner (me) HHR-SS with the 4T45E 4-speed automatic transmission. Felt like I was being rear-ended hard. Turning off the engine and ignition, then restarting the car after 5-10 seconds and problem was gone (until the next time, often after stepping on the gas hard). 3-4 up-shift was always OK, however. Replaced intake cam actuator when trouble code appeared---little better. Re-flashed the ECM, little better---for a while. Still not cured by a long shot. I lived with the problem until last month when the transmission started making a slight whirring noise in Park, followed 3 days later by no Reverse plus balky forward gears. To the transmission shop on a flat-bed tow truck. Dropped the transmission pan and out came metal shavings and chunks of metal. Gear teeth were all chewed up. Had the transmission completely rebuilt including gear sets, clutches, seals, solenoids---everything plus a new torque converter and a new radiator (I didn't want to take the chance of the rebuilt transmission overheating due to metal pieces in the old radiator's transmission cooling passages)---besides, it was car's original radiator and it had 103,000 miles on it. Replaced all the factory coolant hoses, too, most importantly the ones that were easier to reach with the transmission out. HHR-SS runs like new now. And no more hard, banging up-shifts. Ultimately, there was no cure to be had for the hard shifts other than pulling the transmission and having it rebuilt (including having the internal electronics/solenoids replaced).

 

Ok, thread closed, done like dinner.