This is my first post on these forums as it seems to be a pretty thorough resource for Colorado owners. I own a 2008 Colorado, 170k miles, I5 3.7L. She's been pretty good to me until this year when it started overheating. It started back in the summer so I replaced the thermostat and flushed the radiator, standard procedure. It helped, but didn't completely rid it of the overheat. Fast forward to about a month ago, and the overheat is now pretty bad, as in now I can't drive any more than 30 minutes before I'm hitting red. I can smell coolant leaking and in the picture included in this post, I get a good spillage from the "weep hole" positioned below the heater core, making me think my heater core is shot. On top of the overheat, the blower stopped working in the cabin (more on that in a second). I took the car to the dealership for a diagnostic and they said 1) my fan clutch was toast and 2) the blower motor AND resistor was bad. After offering to repair it for $1300, I said "No thanks" and immediately purchased a new fan clutch and installed it. Again, the problem got better but it did not completely fix the issue, it just slowed down the amount of time it took for it to overheat.
Now, about the blower motor/resistor.... I've heard they can burn out due to a bad ground. The other day when it overheated very badly before I could park it to cool off, I got the alert "AC OFF" on the dash.... But my A/C hasn't been on in weeks since the blower stopped working... This got me thinking: "What if there is a bad current to ground from the AC compressor, causing it to 'be on' without really being on and in fact is seized, putting a greater load on the belt system and not allowing the fan/water pump to spin freely?" This is further buttressed by the fact that I have noticed that if I were to turn the defrost on with my blower motor off, the A/C line ices up... A seized AC compressor could cause condenser failure/radiator failure/increased load on the serpentine system...
There is a shit ton going on here but I am at a loss for where to go now. It seems it could be anything I've described and I need a course of action... Thank you all in advance, and if this has been remedied in another post please tag me in it.