Selective overheating

2006 CHEVROLET AVALANCHE
197,000 MILES • 5.3L • V8 • 2WD • AUTOMATIC
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BROKE G
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  • 1 POST
My truck overheated Friday from a lack of fluid in the radiator. I know, I know, I never had a problem before so I haven't checked it regularly. Anyway, that day after getting the water needed it ran fine all day. Saturday morning the A/C wasn't turned on. But on way back from town when I turned the ac up from 1 to 3 or 4 setting the temp went from 208 (normal) to 240-250 pretty quick. What could be the cause mostly?
Coolant temperature sensor, relay, some other switch, etc?
Thanks in advance.
Oct 20, 2019 at 8:28 AM
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KASEKENNY
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  • 18,907 POSTS
Hi,

We need to find out if the temp is actually getting that high. Get an infrared temp gauge and when the temp gauge shows this high, measure around the engine block and see if there is a hot spot or if it is consistent around the engine. Then let me know what the temperature actually is. That will tell us if there is a mechanical issue or a possible sensor issue.

https://www.2carpros.com/articles/how-to-use-an-infrared-temperature-meter
Oct 21, 2019 at 2:19 PM