Creeping temp gauge

[clinebarger]

You did say it's never done this before, But have you ever sat in a drive thru that long in those exact conditions before?

Turning on the A/C would have allowed the fans to operate on A/C Head Pressure, And I bet that would have stabilized the coolant temperature.

I like my low speed fans to come on right at thermostat regulating temp (Which is 195° on LSx engines) & off at 180°, This keeps the 6.2L in my Camaro at a rock solid 200° with a Radiator & Fans half the size of the ones in your Suburban. It does keep the low speed fan operating just about all the time unless the Fan off vehicle speed threshold is met.

I don't replace many thermostats on LSx engines & work on A LOT of them. And when I do.....It's because the water pump is getting replaced.

 

[mfewtrail]

If this is normal operation, why would the temp gauge swing back and forth so drastically? Does this sound like a thermostat issue? It's a cheap part to replace...

205-220 isn't drastic when sitting for an extended period in summer heat without the ac on(fan running). Almost every vehicle with stock programming using electric fans will have temperature swings like that when sitting idle in hot weather with no airflow across the radiator. My car has about a 10*F temp swing in those conditions for example(my fan turn on temperature is a bit lower than yours is the only difference).

 

[admzn]

In my Xterra the engine would run warm at idle or in traffic only with the AC on. It was the fan clutch starting to go. I just re did the cooling system on my Golf, which has electric fans. It does something similar to your suburban where the temps swing up and down, never over 215F though, as the fans cycle. But the coolant temp gauge stays right where it always is. I was watching this from the scan tool. Are you able to get a cheap scan tool and use torque or something on your phone to watch the actual coolant temp? I find the gauges have smoothed readings these days to stop warranty claims of "overheating". They only really move when something is really wrong.

 

[dja4260]

While driving yesterday, no AC on, the temp gauge dropped below it's normal operating temp, then swung back up to where the needle normally sits. The car was at normal operating temp. Thoughts on this occurrence?