Coolant Temperature fluctuations

[gatorbait]

2011 with 80k odometer I've had it since it only had 43k .this summer I've noticed if im stuck in traffic in gear the temp gauge will jump up a couple times the longer I sit the higher it gets .a/c on or off doesn't make a difference and the fans seem to be operating as required.if i turn the heater on it ticks back to normal pretty quick. Once I'm moving at speed no issues it stays just under mid range on the gauge. I just replaced the thermostat last spring ,but the antifreeze is a lil on the light side . It doesn't loose any coolant at least not enough to notice over the summer may have to top off the reservoir each spring but not much .I'm thinking my water pump may be going bad ? Any ideas? Thnx

[Sanford]

From my experience with these things, the gauge will not move when the water temp is between 180F to around 225F. It is best to get a scan tool that will read data and see what the ECM is seeing. If the gauge is moving to the middle of the gauge, you are pretty close to 230F. I had one car get warm on me while charging the AC system after a compressor change. I had pulled the bottom hose to give me a little more access and did not keep an eye on the coolant level. First time in 6 years I had seen a gauge move from its “normal” spot. Even in 100 degree heat driving 90 mph on I10 to Florida, the gauge does not move.

[gatorbait]

1 more reason to purchase that HP tuners package I been looking at I guess.
Never had mine move past just below half Gage until this time does fine on. The highway until I pulled off and stopped to reset my maps did put it in park or neutral just left it in gear . within 1 minute it started climbing got about 3 quarter up and I started driving again it dropped right back to under halfway.so tried it again this time in neutral same thing took a lil longer tho. Tried it again in park with the ac running took about 7 minutes but same thing soon as I turned the heat on it dropped right back to normal. I'm thinking either my pump is getting bad ,or fans may not be reaching top speed ,or maybe coolant isn't thick enough?? Gonna start with the last first I guess.

[Sanford]

All of the OEM LS water pumps I have pulled apart have had stainless steel impellers which pretty well rules out a bad pump. I would check the coolant level in the radiator when it is cold to confirm the system is full of coolant. If the fans are working correctly, you will definitely hear them when they go to full speed. If you plan on driving the car for years, I would invest in a scan tool that will read all of the modules in the car. HP Tuners will do read all of them.

[Mooseman]

You can get true temps by going into engineering mode. While holding the OK button (left roller), start the engine. You can scroll through the different readings.

I'd be checking fan operation, which is what this sounds to me. 2011 did have an issue with failing fan motors because of the idling cops do. Pull the plug and apply 12V to each to see that they can operate at full speed.

[s/c'd cav]

1 more reason to purchase that HP tuners package I been looking at I guess.
Never had mine move past just below half Gage until this time does fine on. The highway until I pulled off and stopped to reset my maps did put it in park or neutral just left it in gear . within 1 minute it started climbing got about 3 quarter up and I started driving again it dropped right back to under halfway.so tried it again this time in neutral same thing took a lil longer tho. Tried it again in park with the ac running took about 7 minutes but same thing soon as I turned the heat on it dropped right back to normal. I'm thinking either my pump is getting bad ,or fans may not be reaching top speed ,or maybe coolant isn't thick enough?? Gonna start with the last first I guess.

LMAO !!! HPT will not fix the way the OE guage works , only hacking into and understanding the programing in the cluster will fix the way the gauge works

the gauges are programed like idiots drive them , only time GM gave up the ability to make the gauge read what our minds tell us is right was on the C5 vette , and for the VOLT gauge , because they alot complained the voltage at the battery was not what the gauge displayed , so they made it easier to change

[gatorbait]

At least I could monitor fans kick and speed in real time making adjustments.coolant level is fine mix is good and according to previous comments the pump impeller should be ok being stainless and low miles and hours .gonna purchase the hp pak anyway as one more tool iny bag .car is going in garage soon for did and cat delete still debating on 8ntske upgrading. Thank you

[JoeR]

At least I could monitor fans kick and speed in real time making adjustments.coolant level is fine mix is good and according to previous comments the pump impeller should be ok being stainless and low miles and hours .gonna purchase the hp pak anyway as one more tool iny bag .car is going in garage soon for did and cat delete still debating on 8ntske upgrading. Thank you

In the grand scheme of things, HP Tuners is a decent scanner for the $400.00 price tag. It's only engine and trans coverage, but it has decent bi-directional controls, and it has every bit of OEM data on those 2 systems. You don't need a license to scan your vehicle, but for the extra $100.00 to license your car it's probably worth it. Even if you only used it to keep the TCC locked in 5th and 6th it would be worth it. That alone would probably save you from an early teardown of that trans.

Joe