Maxifulmax

Hey there, I’m new here but I’ve been ghosting this forum for years for help with my 2007 HHR. My issue today is that after installing a new thermostat and new coolant; my coolant gauge randomly stopped reading the temperature. My coolant is topped off, again new thermostat and the only code is for that thermostat. Did the thermostat fail? Do I need to burp the car? Need help because I’d like to pass my emissions test!

Oldblue

Burp the coolant, please confirm you installed an AC Delco 131-158 180 degrees thermostat and 50/50 Dexcool.

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


Easy stuff first!

Maxifulmax

Yes coolant and thermostat were Dexcool/Delco.

donbrew

If the digital reading goes --- either the t-stat is stuck open or the temp sensor is having problems. You may have disturbed the wires while changing the t-stat.
Tiny possibility an air bubble is circulating.

Not just "Delco", needs to be the correct part number; they make several "interchangeable" parts.

Maxifulmax

Okay, so the t-stat can be working correctly but if the temp sensor is out or the wires were disturb. It would not read a temperature on the gauge?

Oldblue

Correct, the sensor is in the backside of the cylinder block , it can be changed from the top.

Maxifulmax

Final question, so hypothetically if the car hits something hard going fast or accelerates from 20 to 70 miles per hour. Would that cause the sensor to go haywire? Or did it just straight up die?

donbrew

Loose connection.

Oldblue

I found mine had a loose connection, then a month later, the sensor died.

with a 19 mm deep socket, I could remove the old one, an plug the hole with a finger while I positioned the new me and threaded it in then tightened it up, after a test drive , I burped the coolant.
With the rad cap on, I didn’t loose much coolant, I did place a catch pan under the HHR to catch most of the Dexcool

RJ_RS_SS_350

Is it possible that the thermostat is installed upside down, would that cause this issue? Just spitballing.