2004 Blazer 4 door 4WD. I am having an overheating situation. When driving on the highway mostly when the temperature is 85 or higher I noticed that the temp gauge runs a line or two over the mid point. After slowing down and while driving slowly in a parking lot the temp continued to rise to 3/4 and then boiled over. I had added regular coolant and then discovered the coolant in the cooling system turned to a muddy looking solution. i had the cooling system flushed and the shop told me the coolant was still cloudy after flushing several times. I have replaced the thermostat and radiator cap but the same situation continues to occur. I have experimented with having the air conditioning on and off. There is definitely an improvement when the air conditioning is off. It seems like the temp will come down and not cause a overheat or boil over with the air conditioning off. I think it is time for a new radiator. Could there be anything else to consider before radiator replacement? Fan clutch or water pump? Any suggestions or similar experience would be appreciated. Thank you

 

Most likely the radiator is plugged with crud which might require replacement. There's a complicated procedure for doing a chemical flush but it doesn't work all the time. Mixing regular antifreeze with the orange dexcool turns to sludge.

 

Make sure the engine fan is operating correctly.