Code P0128

2011 CHEVROLET IMPALA
100,000 MILES • 3.5L • 6 CYL • 2WD • AUTOMATIC
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VLONGLEY
  • MEMBER
  • 1 POST
Engine hot A/C off light on, temperature gauge drops to zero, AC does not blow cold. I have replaced the thermostat two times drive approximately two hundred miles light comes back on and throwing same code. Replaced ECT sensor drove approximately fifty miles same thing! Hate to keep throwing parts please advise.
Apr 9, 2018 at 8:38 AM
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ASEMASTER6371
  • ✓ASE Certified Mechanic
  • 52,796 POSTS
  • ASE Certified Mechanic
Good afternoon.

It sounds like the thermostat was your original issue. it sounds like it has overheated a couple of times.

The code is for the cooling system not reaching normal operating temperature. the fact that it goes cold while running tells that is setting the code.

You may have a damaged head gasket from the failed thermostat. I suggest you have someone do a leak down test on the cylinders to see if you have a leaking head gasket.
That is where they inject air into a cylinder at about 125 lbs and watch for movement in the coolant. if there is, you have a leaking head gasket.

Roy
Apr 10, 2018 at 2:16 PM
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