743 running hot

[oracle_of_ferndale]

743b has been running very hot since I replaced the head gasket and a freeze plug. I replaced the sensor, noticed that it did not have a thermostat to replace (I did not add one), and replaced the water pump. Also added an electric cooling fan on the radiator. Still runs hot. Checked the temp with a noncontact thermometer and the sensor/gauge are accurate. When replacing the water pump, I noticed the coolant was brown rust-colored. I flushed the system until the water ran clear, but the coolant has not discolored like this before. Is rusty coolant a symptom of another problem? What should I try next?

 

[rjitreeman0909]

Suspect radiator is plugged with rust. Run until hot, then spray a mist of water onto the side of radiator you can see and watch the evaporation or drying. May only see a few of the cores passing water and drying the water. Alternately take machine/radiator to a radiator shop. They can flow test and determine how open or plugged it is. Proceed based on results of either test.

 

[oracle_of_ferndale]

Suspect radiator is plugged with rust. Run until hot, then spray a mist of water onto the side of radiator you can see and watch the evaporation or drying. May only see a few of the cores passing water and drying the water. Alternately take machine/radiator to a radiator shop. They can flow test and determine how open or plugged it is. Proceed based on results of either test.

You were correct treeman. plugged up radiator. Tried running radiator cleaner through there and flushed it again. It ran at the high end of normal temp while idling for a while, but never got where it should be. taking radiator to shop on Monday. Thanks.

 

[Tazza]

You were correct treeman. plugged up radiator. Tried running radiator cleaner through there and flushed it again. It ran at the high end of normal temp while idling for a while, but never got where it should be. taking radiator to shop on Monday. Thanks.

Brown coolant just means the previous owner didn't do a good job with keeping it changed or even put just water and not coolant causing rust to form.
I was going to suspect a plugged radiator too, the hardest part will be getting it out, it's not a fun job to access all the parts.