I keep getting a signal that my hummer H3 2007 is over heating -
the gauge goes up to the red and I get the "engine is hot" warning.
after replacing the sensor, the fun clutch, cleaning the radiator and checking the engine's pressure we found out that all the systems are fine but the warning still shows and the gauge still goes to the red zone.
we run a full diagnostic and found out - again, that all the systems are working fine and that while we get the warning that the engine is over heating the actual temperature of the coolant as well as the engine is 108 Celsius.
What should I do next?

 

How did you clean the radiator?

Did you replace the thermostat yet?

 

Have you tried disconnecting the battery wires and touching them together for a few seconds, then wait a minute or two before reconnecting to reset everything in the computer? It has worked before for others on various other weird electrical issues. Quick and easy to check.

 

Hmm, I just did the math on that 108 Celcius coolant temp reading, that's about 226 F then, right? If the H3 has a 190 thermostat and likes to run around 210, then how hot is 226, right up near the red? Sounds kinda hot to me. Wouldn't that mean that the system is reading correctly?

 

Does your truck go off road at all? I would re-check the radiator again. Like theBroken said, how did you clean it? For the longest time my truck too did the same thing. I cleaned out the front of the radiator for hours and still had the same issue. It wasn't until I pulled back the fan shroud and saw a cement wall of sand and mud caked to it. After I cleaned that out, my problem went away. Hopefully yours might be the same way and it will be a simple fix.

 

For others that might be having this problem, this is something to possibly check.
‪Hummer H3 Radiator cleaning‬‏ - YouTube

 

When my 08 Alpha was overheating I had my Superchips Cortex hooked up so I could read the engine cooling temp. Just before red I was @ 250 degrees. So 226 is a little high but should not be in the red zone nor give you that DIC message. Hmmmm....gotta think about this one.

 

Thanks for the video, Brodie. Now if I can get that grill off....

 

(4) 10mm blots. Two in the front that you can see through the fins. The other 2 are under the hood rite in the corners where the hood, fender and grille meet up. Once the 4 bolts are off grab the edge around the turn signal and pull out There's 2 clips on the very outside of the grille on each side. Then do the same on the other side and it will be loose. The clips are very high quality, you can reuse them hundreds of times before they need replaced.

 

108C is kind of high...operating temp should be between 80-100C....even though Mercs all tend to run up to 110C, and that is normal...108C is definitely on the high side..