I took my hhr to a mechanic. There was a Code p0128 he said he fixed it. He said it was my sensor, my sensor wiring and he said my AC harness. My 2008 hhr coolant reading on dash and needle dropped down to (_ _ _) and my AC went out at the same time. He said he fixed it. My car normally for 3 years(when I bought it) has read at 198 normal reading now it's reading 180-189 and AC has stayed on been 2 days. I drove it the 50+ miles and my husband check the code is still there. What could the problem be that also when the coolant drops so foes my AC???

 

Thermostat... Make sure you use the AC Delco brand. These cars are very particular about that.

 

Welcome to the site, you need a new thermostat, make sure it’s an AC Delco 131-158 . Here’s a how to change it.

https://www.chevyhhr.net/forums/how-...l-p0128-24493/

Then , get yourself a new mechanic!! Your AC will not work because of the code.

 

Thank yall. I figured that was the problem.

 

The thermostat or your mechanic ?

 

Both! Lol

 

As you see in that how to, all you need is a long arm and a 10 mm wrench, now a 1/4 drive ratchet, extensions and a 10mm socket are even better, so you can do this yourself, just put a drain pan under there, ( I just made you say underwear) to catch the Dexcool.