I need help, got in my HHR started driving. Engine light came on, looked at the water tempature it's not reading, clicked on down to the digital coolant gauge it's not reading. Could this just be the thermastat ?.

 

Its the thermostat. The check engine light code will be low coolant temp. I forget the code number. Its covered under the powertrain warranty. I just had mine replaced on my '07
by the dealer about 3 weeks ago.

 

Right on - it is most likely the thermostat. See thread:
https://www.chevyhhr.net/forums/show...ght=thermostat
which includes details on how to replace the thermostat.

The code it will throw due to the thermostat is P0128.

It is caused by the rubber gasket on the movable valve in the thermostat deteriorating, and blocking the thermostat in the OPEN position, which results in the car not getting up to temperature fast enough.

If your car is still under warranty, it will be covered by the dealer.

 

Sounds like this system has been used by GM for a while. I had an 01 Monte Carlo that the same thing happened on. Stat sticks open and it goes into fail safe mode. Turns on the radiator fan to help insure that it does not overheat since it cannot tell.

 

Well it's not the thermostat, i just replaced it with a new one and still no readings.Even checked the fuses. Any other ieda's?

 

check the codes. it may be a bad coolant temp sensor

 

Did the engine check light come on? If so you need to get the error code reD by a code reader. Autozone stores will read the codes for free apparently. If the engine check light was never cleared after replacing the thermostat, you need to clear it - just disconnect the NEGATIVE battery connector in the trunk for a minute or two.

 

Won't the light clear itself after driving for a while?

 

I don't know if this is the same problem I am having but sounds close. I have tried to have my error code read by autozone on several occasions, and even NTB with there more expensive ones and it will not pick up anything. No signal. The thermostat still works (mech) but the display does not work, neither the digital or the old style on the dash. Mine also has a secondary problem attached to it that you may not have noticed if it just started happening since it's cold. Whenever that system goes out my ac does not work. I can turn it on, but the compressor never kicks in and it just circulates air. Mine has been doing this over a year, and we haven't been able to figure it out, and don't have the money to take to have a dealer and let them run up a bill trying to figure it out. Mine comes and goes. Not sure why or what triggers it though.

 

All better now. After replacing the thermostat, I drove the around the block and the gauges came back to life but still had the engine light.Tried clearing it bu doing the battery thing didn't work.Went to the dealer, it was throwing two codes.1 for the coolant flow( replaced thermostat again)2nd fuel mixture ( dirty fuel injectors ). Now it runs like a champ.