Cooling System/Overheating Issues

Tiny
JONATHAN HAWTHORNE
  • MEMBER
  • 1999 CHEVROLET LUMINA
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
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.
Monday, July 18th, 2022 AT 8:54 AM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,070 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.

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Monday, July 18th, 2022 AT 4:29 PM
Tiny
JONATHAN HAWTHORNE
  • MEMBER
  • 3 POSTS
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.
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Monday, July 25th, 2022 AT 8:21 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,070 POSTS
Sounds good, let me know if you need any more help.
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Monday, July 25th, 2022 AT 1:06 PM
Tiny
JONATHAN HAWTHORNE
  • MEMBER
  • 3 POSTS
Why would my new coolant level sensor leak?
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Monday, July 25th, 2022 AT 3:50 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,070 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.
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Wednesday, July 27th, 2022 AT 11:29 AM

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