2004 Chevy Impala Temperature Gauge Goes From Half To Full Hot

Hi there. this is a cooling system issue. I just purchased a 2004 Chevrolet Impala basic. There is only water. No coolant in the radiator. The temperature gauge fluctuates from half way mark to the 3/4 mark. However when I stick a calibrated bio-thermometer in the over flow tank the temp only reads 118 F at it`s hottest point after idling for 15 minutes. And when I check it with the live data on my scanner it temps out at 213-220. does this sound like a faulty coolant temp sensor ?

First of all, you should really get the mixture correct before doing any testing on the cooling system. I would recommend at least adding 50/50 mix of coolant and water and then check again. The over flow tank is not the place to check a temperature reading either. The coolant would have cooled somewhat before it reaches the tank. The live data reading seems like it’s about in the right place. You may just have a gauge that is a bit off.

OK. When I drain the coolant should I check the thermostat for gasket wear also ? And what should I do if i get the same results after the coolant change ? Thank you.

I really think you’ll be fine. The temperature that is it currently running at is normal (220). I’m pretty sure your thermostat is ok since you do have flow and heat. If it was stuck open, it wouldn’t reach operating temp and would set a code. Stuck closed and you’d be overheating. I’d recommend getting a proper mix in the system, and you should be just fine.

The gauge on the dash is never exactly as correct as the coolant temp sensor. It may be high or low compared to actual. If it runs near the 3/4 mark but the car is still only 220 degrees, you know you’re ok.

Awesome, thanks.

You’re welcome!

I almost forgot. This is a weird one I never seen before. My wipers will not work on the 2004 Impala 3.4L on any speed. However, they will work when I push the button/switch to spray washer fluid. I checked the fuse and it is good. They will go like 3 swipes then stop.

Lucky you asked when you did, because live chat is closing in a moment…As for your problem, you could need a new wiper switch, or you could have a problem inside the control module which is part of the motor assembly.

Thanks and good night. What time est. do you guys start.

Again you’re welcome….We are only here on Tuesday and Thursday nights at 8pm eastern. If you have a question, you can register for our forums and ask it in there. Thank you and good night.


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5 comments to 2004 Chevy Impala Temperature Gauge Goes From Half To Full Hot

  • Live Chat

    Hi, i have Chevrolet Caprice 2001 sometime temp gauge goes more than half or around 60-65% is it ok?

    ProTech: A little bit over halfway on the temp gauge should be fine. Even 3/4 is not detrimental, as the gauge is never as exact as the the actual temperature sensor. I would only be cautious if the gauge starts to go past the 3/4 mark and head towards the red. Then you would want to get it checked out before any damage occurs.

  • Joan Christian

    When I start my car the water temperature gauge is already in the red hot zone and continues to bypass the red zone and faces downward toward the floor as the car warms for less then 3 minutes. Checked and filled the 50/50 anti-freeze and still does this. I’m afraid to drive my car. Sorry it is a 2004 Chevrolet Impala 3.4 liter, V

    • ProTech

      If the gauge starts in the red when the engine is cold, you either have a bad gauge which is part of the instrument cluster, or a bad coolant temperature sensor.

  • Embrie

    hopefully i get a quick response, on the alero there are only 3 scewrs to remove right? i have them all out and just want to make sure that’s it, i’m pulling on the bottom of the panel and it’s not budging, just want to make sure i have all the scewrs out before i break something haha

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