My olds is overheating when it is when it is just idleing. The temp comes down once I start moving again or if I turn on the air. Is this a sign of a bad fan or possibly the thermostat?

Top off coolant and start monitor for coolant loss and white smoke at tailpipe.
Lost of coolant and white smoke is a sign for blown head gasket.

Start by checking to make sure that the a/c condensor and radiator is not full off debris. If the condensor and radiator were full of debris it will limit the air flow from the engine cooling fan which in tern will cause a high discharge pressure on the discharge on the a/c causing poor or no cooling at idle and could also cause vehicle to overheat. Check and make sure that the cooling fan as well as the condensor fan are coming on together when the a/c is turned on if equipped with 2 fans.

For car running hot and overheating issues, I suggest to you go through this help links. Click this link below and go through the troubleshooting procedure to take care of the problems: ----

temp gauge goes erratic? http://technoanswers.blogspot.com/2012/01/heater-blows-intermittently-and-temp.html

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Temperature gauge keeps fluctuating up and down close to red? http://technoanswers.blogspot.com/2012/01/temperature-gauge-keeps-fluctuating-up.html

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Car runs hot? http://howtobyme.blogspot.com/2011/11/car-runs-hot-in-traffic.html
-----------All types of car overheating problems and troubleshooting?

http://technoanswers.blogspot.com/2011/11/all-types-of-car-overheating-problems.html
Car freeze overnight and started overheating while driving?http://technoanswers.blogspot.com/2012/01/car-freeze-overnight-and-started.html-----------Engine Overheats and heater blowing cold?

http://howtobyme.blogspot.com/2011/11/engine-overheats-and-heater-blowing.html

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Car overheats and Air blows hot at idle?
http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html
--------overheating? http://schematicsdiagram.blogspot.com/2011/12/buick-century-overheating.html
----------Car engine Overheats and transmission starts slipping?http://schematicsdiagram.blogspot.com/2011/12/car-engine-overheats-and-transmission.html
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Temperature gauge does not move and no heat when heater is ON? http://technoanswers.blogspot.com/2012/01/temperature-gauge-does-not-move-and-no.html

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This details will help.Thanks.

For car running hot and overheating issues, I suggest to you go through this help links. Click this link below and go through the troubleshooting procedure to take care of the problems: ----Car runs hot? http://howtobyme.blogspot.com/2011/11/car-runs-hot-in-traffic.html
-----------All types of car overheating problems and troubleshooting?

http://technoanswers.blogspot.com/2011/11/all-types-of-car-overheating-problems.html
Car freeze overnight and started overheating while driving?http://technoanswers.blogspot.com/2012/01/car-freeze-overnight-and-started.html-----------Engine Overheats and heater blowing cold?

http://howtobyme.blogspot.com/2011/11/engine-overheats-and-heater-blowing.html

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Car overheats and Air blows hot at idle?
http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html
--------overheating? http://schematicsdiagram.blogspot.com/2011/12/buick-century-overheating.html
----------Car engine Overheats and transmission starts slipping?http://schematicsdiagram.blogspot.com/2011/12/car-engine-overheats-and-transmission.html
----------This details will help.Thanks.

Welcome to Fixya

Sounds like you have a problem with the cooling system. First thing you need to check first if the auxillary fans are working from the time you are the engine is overheating. If the auxillary fans is not working then the problem would be the aux fan itself or relays. if Fan is working then you might have a poblem with the water pump.

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If you need further help, reach me via phone at https://www.6ya.com/expert/elixirjose_00375ea24bd8141b

this is simple, when the engine is idling there is no air going through the radiator to cool the engine ,but when the car is moving there is air going through the & cools the engine, the problem might be that the fans are not coming on that is why the temp. goes up to 245deg.you will need to find out why the fans are not working, maybe a blown fuse or faulty temperature sensor the activates the fans......hope this helps......cheers.

Start lookig for intake leaks. This is a sign of an air leak and seams like a pretty bad one. Let me know what you find.

You have two fan's on your truck, 1 is a fan clutch runs with the drive belt, 2 elec fan motor, with test light and engine running at normal temp, just a little bit above 1/2 way on your temp gauge check voltage at elec. cooling fan harness if you have voltage at one of the two wire's and fan don't turn on, bad cooling fan motor, on the fan clutch after you check voltage at elec. fan motor turn engine off, with your hand spin drive belt fan if it spin's freely bad fan clutch, replace it.Also check cooling level.Hope this was very helpful

First when vehicle is cold like in the morning check and make sure that the vehicle has enough coolant/ antifreeze in radiator and reservoir. If coolant is need use a 50/50 mixture of water and antifreeze. You will need some time to do this let car run at idle until the temp guage is in the middle NOT+ normal operating temperature. At this point if the thermostat should be in the open position. Let vehicle run and check to make sure that radiator fan comes on. This should come on when guage is about midway/half way. If temperature rises above half going to h/hot and fan doesn't come on, you either have a BAD FAN BAD FAN SWITCH BAD FAN RELAY OR BLOWN FAN SWITCH FUSE. You will need to check all of the following I will help if its needed. If fan comes on and doesn't go off and vehicle continues to get hot even with fan running. Feel radiator hoses and see if the lower radiator hose is cool/cold. If it is you have thermostat that stuck closed. Replace thermostat and fix problem. If all the above is good and vehicle continues to over heat. THE BAD NEW IS THAT YOU MAY HAVE A BLOWN HEAD GASKET /CRACKED HEAD /BROKEN WATER JACKET. Basically you will need a HEAD JOB at least a head gasket. ONe tell tail sign of this is oil looking like milkshake/chocolate milk-a creamish while residue in oil or antifreeze. Contact if you need hel0p. Good Luck and thanks for using FIX YA

check fluid level if full remove rad cap when car is cold and run while looking at fluid in rad if it is circulating you should see it moving if it does'nt move after car warms up thermostat needs to be replaced also check to see if fan is working properly and check the reputation of your mechanic some are not always honest