My Car Overheats At Idle After Driving A While

Posted in Cooling Perfomance | Asked on Jun 6, 2010

My car overheats when I drive for long idle time and then, as in the road or so etwas.Ich’ve never seen the fan again (even when running hot), but I’ve checked the fan motor with a battery, and it is not the Problem.Einige other facts: Yes, there is coolant in System.Ich have checked and replaced the relay – it is not the Problem.Ich have checked and replaced the fuse – it is not the problem.The ad on the dashboard works and tells me that he overheated ist.Also I have heard that there are several other areas for inspection – Thermostats, switches, etc. Can you help me, the perpetrator? Dank.Haben people even bother to full question read? The relay arbeitet.Es no coolant is austritt.Check my oil for what – Gremlins? I my oil every 3k miles and check the level every other pit stop as recommended in general.

There are 10 Answers for "My Car Overheats At Idle After Driving A While"

  1. Sexy D says:

    That mean save your money and get u a new damn car and let go of that old shit and upgrade

  2. Wrenchmeister says:

    The fan should work when the temp goes above the specified limit, Since you do not provide info on the particular car,. I cannot tell you if is either 180 or 210 degrees.

    The elements that make the system are:

    1.- the temp switch
    2.- the fan
    3.- The relay

    4.- In some cars the computer gets the signal from the switch or directly from the temp sensor, and then send the signal to the fan. In those cases, the computer could also be the problem.

  3. italy_coolfun says:

    The fan should definitely be running, especially when hot. Most likely it is the fan relay. Replace this relay and see if it works.

  4. james m says:

    I would bet that you have not checked the bottom radiator hose.It sounds like your bottom hose is collapsing at highway speed (high RPMs).What happens in this case is the wire inside if the hose has rusted away,and this allows the vacuum to collapse the hose stopping the circulation of the coolant.This happened to me on my way from Missouri to Fla. several years ago.If it is not that,and you have checked everything else,it must be the water pump,because if it was a head gasket,you would be losing coolant.So it has to be either the bottom hose or the water pump.

  5. kingofdrifters says:

    If it overheats and it is causing you a problem it might be the water pump. When was the last time you got it changed also if it’s not the radiator then is it leaking from anywhere and check your oil.

  6. robert s says:

    first i like the lower radiator hose thing. had never heard of that but its possible. here’s my list of suggestions:
    1. radiator is not working effectively as the cooling fins have started to corrode. this would cause the car to be fine at highway speeds when there is more than enough air flow. i experienced this a few years back. hence, replace radiator.
    2. thermocoupler is not functioning hence the radiator fan is not coming on.
    3. clog in system that slows down movement of af which would show up worse at idle with no air movement.
    4. water pump is really bad and has worn out impellers causing weak flow. i kind of doubt this but it is possible.
    5. old coolant that reduces cooling effectiveness.
    good luck.

  7. e_boy12 says:

    i have to said it the fan switch it location is by the side of the oil filter it have a two connector on it should be to the left
    there are two of them first one have 1 connector is the stock oil presser unit and the 2nd one is the fan switch if the fuse is good the relay is only for the ac unit since it the fan switch
    u should change the thermostats

  8. Kim C says:

    Maybe you have a crack in your radiator. Sometimes even small thin hairline cracks would make your car run hot. I had that trouble before. You should just take it to your mechanic before you crack your engine.

  9. E. L says:

    Hey dude All the above…….Then Check the Water temp with a thermometer, this will tell you at what temp your thermostat opens, with that you can tell by the elapsed time the condition of the water pump. then with the motor hot replace the radiator cap and check time to system pressure, and check lower rad hose for collapse

  10. deep_respect says:

    If the radiator is not hot when the engine is overheating I would replace the thermostat.

    Otherwise if the radiator fan doesn’t run when the car is hot and you are idling the car is very likely to overheat because there is no air flow through the radiator. If while the car is overheating you connect the fan directly to the battery and it works it should cool the car. If this happens then you know that its definitely that the fan isn’t turning and that is where you should focus. Get a service manual with a schematic diagram (not a block diagram) of the electrical system. A good schematic will show the actual wiring with color codes and connectors which you will need to trace the circuit. Use a voltmeter and start at the fan and work your way backwards. If the fan is driven by a relay there should be voltage at one of the relay contacts when the relay is inactive and voltage at both contacts when the relay is active. If there is no voltage at any of the contacts then you need to check any fuses. If the fuse is good then you check the wiring for corrosion. If this is an older car it could be corroded wiring. Check for power at the fuse and if there is none supply it from the battery. If all checks okay then check to see if power is supplied to the relay coil. If it is and relay doesn’t close then its the relay. If there is no voltage and the car is hot then you need to trace out the wiring to diagnose what is powering the relay. You should also check the temperature sensor. Disconnect the temperature sensor and use an ohm meter to measure conductivity when the car is cold and when it is hot. If you see no difference then it should be replaced. A good service manual should state exactly what to look for.

    Hope this helps

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