Question about 2003 Pontiac Sunfire

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All of the sudden my temp gauge is running 3 to 4 bars over the half way point & is making me nervous. (I know nothing about cars). I recently had my fuel pump replaced. Would that have anything to do with it? I checked the coolant & it's fine. Also, the last 3 days have been in the 20's at night in Vegas. Very cold. Need some advice....

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  • slickchrissy Jan 03, 2011

    The heat works fine. But I'm afraid to put in on in case that makes the engine hotter? Is the engine actually overheating? How do you get the cooling fans to come on, if that's the problem?

  • slickchrissy Jan 03, 2011

    I will turn the heat on when I drive tomorrow morning. Hopefully that will help. From everything I've learned tonight, I think it might be a thermostat problem? Thanks for all your help.



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The fuel pump should not have anything to do with it.If coolant level is ok you may have a thermostat issue or lack of the cooling fans coming on when they should. Does your vehicle heat seem to work ok when you turn the heater on?

Posted on Jan 03, 2011

  • Jonathan S
    Jonathan S Jan 03, 2011

    Turning the heat on will actually help if the vehicle is running hotter then it should.You can check the cooling fan operation by turning the ac on just to verify that the fans do come on. If the fans are not coming on with the ac turned on then we will need to go through some possible testing to figure out why. We can only test the fans like this as long as the air conditioning operates normally.


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Who ever told you that turning on the heat in yor car actually makes the car run hotter is STUPID! the heater for the inside of the vehicle runs off a little fan and radiator inside of your car, which uses the exact same fluid that runs through the entire engine. It is not on a seperate circuit from the rest of the car. Turning on the fan interior heat actually makes the engine coolant get colder because it has some place to disapate, instead of just sitting there and getting hotter....

Now to the engine fan. Your fan there runs on electricity and turns on when your car hits a certain temperature, and is controlled by a little electric sensor that is placed on the radiator and/or cylinder head. The operation of the fan should only be sporadic on days where the temperature outside is cool, and you are driving at normal speeds and not rat bagging your car. On hot days, sitting in slow moving (stop and More Stopping, traffic jams) then your fan will come on and stay on longer, because there is no movement of air across the fins in your radiator, which cause the coolant inside to disapate the heat it is carrying away from the engine.... Turning on the heat inside of your car will actually help prevent your car from over heating (if it already does)... One the car over heats, do NOT OPEN the radiator vent cap, because the radiator is under pressure from the hot coolant inside. You will wind up spilling every single drop of anti freeze onto the side of the road, if ytou open the rad while it is hot. Remember this, if the radiator is too hot to touch, then it is too hot to open the cap. be patient and wait, you will save a ton of grief by being patient.

Posted on Jan 03, 2011


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