2005 Chevy Colorado, 3.5 inline 5, 127,000 miles
My colorado has been having an overheating issue but not what you would expect. My temp gauge only exceeds half if I am sitting at a light for a long time. I have noticed after turning the key off and i put the key in accessory mode the temp gauge needle steadily climes to 3/4. It has no heat. It is not a thermostat as I’ve gotten to the thermostat to replaced and noticed it had been changed, still pulled it and tested it in the boiling hot water and worked as designed. I have a heater core to replace in it I haven’t done yet as that was my next step in terms of there was no heat coming out when you turn it on. I have a feeling this is not the sole issue though. I had to tear into my A/C cluster because it would not turn all the way cold and I found zip ties and the a/c controls were a little wonky which makes me think maybe the heater core had been messed with before. I just bought this truck at 221,000 miles and didn’t notice the issue when i test drove it as it was not hot outside like it is now. The truck is not burning oil, i change it regularly and it’s the same amount I’ve put in (6 qt). Coolant obviously has been changed due to the thermostat pull and radiator bled too. Could this be a water pump issue or is it something simple that I am over looking. For your reference there is a video of me driving it today at highway speed and the temperature is fine and then a picture attached of the temp gauge after turning the truck off and putting the key in accessory. In the video you will notice a check engine light, it is unrelated it’s a P0446 (evap) that i am going to fix next. The a/c is on 2 in the video also. The picture I am uploading is not to the 3/4 mark but it has gotten up there a few times when i put it in accessory. This issue only occurs like i said when im sitting at a light for too long, i put my a/c too high (in terms of air speed), and when i put it in accessory after parking.