How to save $350.00 + (Thermostat Replacement 2.4L - P0128)
Thanks. I'm just surprised, I guess, that if it's a bad t-stat that there's no reading whatsoever on either the gauge or the DIC. I'm really an older car kinda guy used to mechanical gauges. I'll pick up a new t-stat and hope it fixes the problem. Thanks again!

FWIW, when I was about two blocks from the auto parts store, the temp gauge suddenly started working again and the temp climbed steadily from ~170° to the 195° I'm used to. Bought the new t-stat anyway and will replace tomorrow (after the car has cooled down). Sure acts like a stuck t-stat that loosened up again, so this should fix it. Thanks again!
Sorry, didn't mean to imply I was asking for an explanation -- just saying I was surprised is all. 
FWIW, when I was about two blocks from the auto parts store, the temp gauge suddenly started working again and the temp climbed steadily from ~170° to the 195° I'm used to. Bought the new t-stat anyway and will replace tomorrow (after the car has cooled down). Sure acts like a stuck t-stat that loosened up again, so this should fix it. Thanks again!

FWIW, when I was about two blocks from the auto parts store, the temp gauge suddenly started working again and the temp climbed steadily from ~170° to the 195° I'm used to. Bought the new t-stat anyway and will replace tomorrow (after the car has cooled down). Sure acts like a stuck t-stat that loosened up again, so this should fix it. Thanks again!
Let us know how the replacement goes, and if it resolves your problems.
Problem solved. Not quite at easy as an old small-block Chevy, but not terrible by any means. Once I got the old one out, it was obvious that it needed to be replaced (old one on the left, replacement on the right):


Took it for a short drive and it got up to temp right away. Thanks again for the advice!


Took it for a short drive and it got up to temp right away. Thanks again for the advice!
The thermostat is covered by the 100,00 mile warrantee? Even if the vehicle (I purchased new in 2006) is 9 years old? It has 50,000 miles on it.
Hello guys & gals,
I used this thread back in July 2014 to replace the thermostat. About 8000 miles later getting the p0128 code. I picked the thermostat at Adv Auto Parts and it wasn't the ACDelco brand. I did check my coolant levels and seem fine. Anyone else have this issue?
-Also can I damage the car if I keep on driving it like this?
Thanks in advance.
I used this thread back in July 2014 to replace the thermostat. About 8000 miles later getting the p0128 code. I picked the thermostat at Adv Auto Parts and it wasn't the ACDelco brand. I did check my coolant levels and seem fine. Anyone else have this issue?
-Also can I damage the car if I keep on driving it like this?
Thanks in advance.


