Code P0128

VLONGLEY

MEMBER
2011 CHEVROLET IMPALA
3.5L
6 CYL
2WD
AUTOMATIC
100,000 MILES

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.

Monday, April 9th, 2018 AT 8:38 AM

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

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

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Tuesday, April 10th, 2018 AT 2:16 PM