Temp gage fluctuation

[la1]

I have a 2003 LA1 impala (3.4L). I have noticed that all the current Chevys we have and the past ones for the most part after a few minutes driving the temp gage goes to a setting and stays steadiy. My temp gage sort of tracks the weather, when cold it stays on 160 - 170. While durring the summer it usually is around 200 -220 unless freeway driving where it will drop 20 degrees. I have seen other impala's where the temp gage stays at the middle ( 200) no matter what the wheater...our 2006 Malibu also stays at 200 , center of thr gage.

[j cAT]

Originally Posted by la1

I have a 2003 LA1 impala (3.4L). I have noticed that all the current Chevys we have and the past ones for the most part after a few minutes driving the temp gage goes to a setting and stays steadiy. My temp gage sort of tracks the weather, when cold it stays on 160 - 170. While durring the summer it usually is around 200 -220 unless freeway driving where it will drop 20 degrees. I have seen other impala's where the temp gage stays at the middle ( 200) no matter what the wheater...our 2006 Malibu also stays at 200 , center of thr gage.

the thermostats are a problem ...after market T stats are not equal and it I have found requires a high quality part...the low quality part will not correctly regulate the temp..

the other componet is the correct coolant and mixture with distilled water..and coolant system condition.

[la1]

The thermostat is the factory one as far as I know.
I drained the coolant from the rad and block. Filled with I think 50/50 dexcool and distilled water. The strange part was I could not put in the full amount it said should go in ( helm factory manual). I even removed the threaded plug next to the knock sensor to drain the block. When filling I opened the small screw vents on the top rad hose block fiting.

[j cAT]

Originally Posted by la1

The thermostat is the factory one as far as I know.
I drained the coolant from the rad and block. Filled with I think 50/50 dexcool and distilled water. The strange part was I could not put in the full amount it said should go in ( helm factory manual). I even removed the threaded plug next to the knock sensor to drain the block. When filling I opened the small screw vents on the top rad hose block fiting.

this amount should be 3.5 gallons...the heater core /hoses trap 1-2 quarts...

I carefully capture all drained coolant and then use that drained amount to calculate the correct mix...

since you did this properly I suspect that the coolant temp will be better...

[la1]

..thats probably where the coolant was..in the heater core.. I did the same, I used one of those big galanized pans made for such procedures , then poured into a 1 gallon jug, what I got out was also less.

No unfortuately it did not, temp gage still the same.

[j cAT]

Originally Posted by la1

..thats probably where the coolant was..in the heater core.. I did the same, I used one of those big galanized pans made for such procedures , then poured into a 1 gallon jug, what I got out was also less.

No unfortuately it did not, temp gage still the same.

I didn't see that you replaced the thermostat....If not replace with a high quality one as this will keep the engine temp correct if the coolant is good and clean...since you have no operating engine issues this is all I would expect is the problem...these thermostats are good for 4-5years and I usually replace when the dexcool is serviced at the 3-4 year point...on my vehicles..