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Car continues to run hot so I ran the engine block test, compression test and pressure test again and everything checks out well.
Question: I went back and looked at the original water pump that was removed from the hhr
Original water pump
and I noticed that the new pump has a different type of blade. Would that make a difference in how the pump would function? New pump with metal open blades
Do not know where you got the "new pump" but is has the wrong impeller on it. The original pump has the enclosed impeller and is about 40% more efficient.
Do yourself a favor and replace the new pump with an exact replacement pump with correct impeller.
I'm betting all of your problems will "go away".
So I decided I would give one of those head gasket sealers a shot. Picked up Blue Devil from the auto parts store which instructed that the thermostat would need to be removed to use it.
So I removed the thermostat and filled it up with water. It said to drive around for 3 to 4 hours for a more thorough clean. To my surprise I drove around and no over heating.
So I drained the cleaner refilled with coolant minus the thermostat and to my surprise the car has been driving perfectly ever since. A matter a fact it runs almost to cool ( between 165 to a high of 172 ).
The thermostat was replaced twice once with an aftermarket then to be on the safe side we got one from the dealer and put that in and the car kept overheating.
The one issue now with the car running so cool it takes forever for the heater to start working but the AC blows cold as ever. Someone once told me that the car would not even give a coolant reading without the thermostat but that's not true it reads perfectly and runs perfectly without the thermostat again ice cold AC.
So now I am concerned about putting in another thermostat.
Should I continue to drive the car without it or am I doing some kind of damage to the system?
Running without a thermostat is probably allowing the cooler engine temps to hide the real problem.
With the onset of cooler weather, because of the longer warm up times, I would be surprised if you don't eventually throw a CEL. P0128.
I would suggest getting another AC Delco stat and installing it.
I took it out for a long drive today just after posting and once I engaged the cruise control the coolant readout on the DIC went to lines as I expected it to do before. I have an ELM odb II adapter attached to the port that gives coolant readouts despite the lines on the DIC and still the highest the temp got to was 181.
So now the AC no longer is working but the car is running perfectly without overheating.
Don I never used the Bluedevil because once I removed the thermostat to flush the system, that was the end of the overheating. I just flushed it and added water.
What do you consider over heating? The cooling fan is supposed to come on at about 219F and run until the t-stat CLOSES at 180F. At 179F you are running TOO cool.
Once again; a t-stat keeps the temp over 180F. If yours happened to fail CLOSED or somebody put a 190F t-stat in it might cause overheating or if the cooling fan is not operating.
The reason you have a P0128 is that the engine temp is not getting to 180F fast enough.
10-02-2017, 07:36 PM
