Cooling System/Overheating Issues

1999 CHEVROLET LUMINA
160,000 MILES • 3.1L • V6 • 2WD • AUTOMATIC
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JONATHAN HAWTHORNE
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I recently purchased this car from a friend because it was cheap and I needed a car. Overheating issue from the start. First I noticed coolant leaking from water pump so I replaced it and did a coolant system flush. I replaced the coolant temperature sensor & thermostat even though the thermostat was still good when i flushed the system. Shortly after flush cooling fans stopped coming on automatically. All relays & fuses checkedbout good so I wired the relay to cooling fan #2 to a switch inside car so I had 1 fan I knew was working. Still wanted to run hot, upon inspection I noticed a crack in the radiator so I replaced it. So now I have a new radiator, thermostat, coolant temperature sensor and water pump but my car still seems to be running hot @ 240-250 but it doesn't overheat needle never goes into the red. I dont have any leaking coolant, coolant level is good haven't needed to add anymore and there is no coolant in the oil. I am confused by this and slightly concerned because I don't want to damage my car but I don't know what else could be causing this. I was looking at parts and came across a cooling fan console module but cannot find anything online about this and I'm not sure where it is at. Your expertise will be greatly appreciated.
Jul 18, 2022 at 1:54 AM
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STRAILER
  • Experienced Mechanic
  • 55,273 POSTS
I know the coolant gauge might say it is over heating or running hot, but they had troubles with the gauges in these cars reading hotter than actual temperatures. I would start the engine and allow it to warm, note the temperature gauge readings and the use an infrared temperature gun and point it at the thermostat housing to take a reading, please let me know what the difference is if any. In the meantime, here is a guide that can help:

https://www.2carpros.com/articles/how-to-use-an-infrared-temperature-meter

and

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please run down these guides and report back.

Jul 18, 2022 at 9:29 AM
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JONATHAN HAWTHORNE
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I have not yet gotten an infrared temperature gun but my coolant level sensor was bad so I changed it and now it leaks from coolant level sensor. Now I'm dealing with a P0300 random misfire code so I cleaned the ignition coil terminals lubed them up with dielectric grease and put back together. Temporary fix until I can replace plugs & wires.
Jul 25, 2022 at 1:21 AM
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STRAILER
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Sounds good, let me know if you need any more help.
Jul 25, 2022 at 6:06 AM
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JONATHAN HAWTHORNE
  • MEMBER
  • 3 POSTS
Why would my new coolant level sensor leak?
Jul 25, 2022 at 8:50 AM
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STRAILER
  • Experienced Mechanic
  • 55,273 POSTS
Does it have a new O ring? Is it the sensor itself? If you can upload a picture of the problem I can tell for sure. Here are the instructions for the sensor replacement, maybe we can look to see if something is a miss? Check out the diagrams (below). Please let us know what you find.

Jul 27, 2022 at 4:29 AM
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