[LiquidRS]

As this is the first winter with my car, I've observed a rather odd coolant temp gauge behaviour. Its now sub 25 degrees C here and when driving the car with lots of airflow on the highway the temp gauge moves from its 1 min to 11 position to maybe 3 minutes to 11. If I increase the pace somewhat it settles at its usual 1 minute to 11 position. Given that this is a dumb gauge Im surprised at how sensitive it is.


Is this normal behaviour or do I have a thermostat that's stuck open? No warning lights etc and it reaches 90 degrees C within 5-10 min of gentle driving. Pics below. First pic is the drop in temp cruising on the highway after its reached usual operating temperature. i'm not too concerned but I just want to understand the cooling protocol for the LT4.

[ctrlz]

Originally Posted by LiquidRS

when driving the car with lots of airflow on the highway the temp gauge moves from its 1 min to 11 position to maybe 3 minutes to 11. If I increase the pace somewhat it settles at its usual 1 minute to 11 position. Given that this is a dumb gauge I'm surprised at how sensitive it is.

Wow! Great that you are paying attention to your gauges!

This variation I would consider normal. My 2SS does the same thing. The thermostat is the "dumb" device here. It has a "cracking" temperature, where it just begins to open, and a "fully open" temperature. Maybe 194 for cracking, and 210 for fully open. The way it performs will be affected by the temperature of the metal surrounding it as well as the fluid trying to get past it. When the air in the engine bay and the air coming through the radiator are both 10 degrees and I am cruising, it does settle at a slightly lower temp compared to a 90 degree summer day.

EDIT: I apologize for using Fahrenheit for all my temperature references!

[SOCAL.M6.ZLE]

Originally Posted by ctrlz

Wow! Great that you are paying attention to your gauges!

This variation I would consider normal. My 2SS does the same thing. The thermostat is the "dumb" device here. It has a "cracking" temperature, where it just begins to open, and a "fully open" temperature. Maybe 194 for cracking, and 210 for fully open. The way it performs will be affected by the temperature of the metal surrounding it as well as the fluid trying to get past it. When the air in the engine bay and the air coming through the radiator are both 10 degrees and I am cruising, it does settle at a slightly lower temp compared to a 90 degree summer day.

EDIT: I apologize for using Fahrenheit for all my temperature references!

Well said. The factory gauges do not show the actual temperature in real time. They are slow to adjust as to not alarm the driver. If you want to know your real-time temps, I suggest you look into the Banks iDash guages. I have two of them... they are amazing! Hit me up if you want more details.

[LiquidRS]

Originally Posted by ctrlz

Wow! Great that you are paying attention to your gauges!

This variation I would consider normal. My 2SS does the same thing. The thermostat is the "dumb" device here. It has a "cracking" temperature, where it just begins to open, and a "fully open" temperature. Maybe 194 for cracking, and 210 for fully open. The way it performs will be affected by the temperature of the metal surrounding it as well as the fluid trying to get past it. When the air in the engine bay and the air coming through the radiator are both 10 degrees and I am cruising, it does settle at a slightly lower temp compared to a 90 degree summer day.

EDIT: I apologize for using Fahrenheit for all my temperature references!

Thanks for your response. So perfectly normal then.

[ZLRob]

Manual dash temperature gauges have stopped being accurate for a number of years on vehicles. I don't know why they decided to do that but that is also the case on our vehicles. It's not cool because it prevents the end user from accurately gauging whether or not they are in an overheat condition until it is far too late and damage has occurred. I strongly recommend the iDash gauges as well as you will see your true temps in real time as SoCal indicated. I have one on mine and I always see the temp rise up to what it is supposed to be for my specific operating temps whether winter or summer.

[LiquidRS]

Originally Posted by ZLRob

Manual dash temperature gauges have stopped being accurate for a number of years on vehicles. I don't know why they decided to do that but that is also the case on our vehicles. It's not cool because it prevents the end user from accurately gauging whether or not they are in an overheat condition until it is far too late and damage has occurred. I strongly recommend the iDash gauges as well as you will see your true temps in real time as SoCal indicated. I have one on mine and I always see the temp rise up to what it is supposed to be for my specific operating temps whether winter or summer.

Yes these dumb gauges are a waste of real estate. Simple warning lights would probably have the same outcome. On a positive note the oil temperature gauge is real time so I use that as a leading indicator of overall under hood temps and limit it to 125 degs.