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Q: jumping engine temp between idle and drive

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after waiting in idle for 45 minutes engine temp shoots to almost max. then falls to mid temp as i drive and only to steady climb up as I sit in idle again just had fluids checked and topped a few months ago would this be a problem

My car has 192000 miles.
My car has an automatic transmission.

Anytime there is a temperature issue with a car, the first thing that should be done is to confirm the cooling system is full. This should be done with the engine cold. It is dangerous to check the coolant level when it is hot. If the cooling system is low, it needs to be filled and the leak found and repaired.

If the cooling system is full and you are experiencing these problems, you will need to confirm the thermostat is working properly. If it is, the next suspect is the radiator fan. The fan is used when the car is at a stop. It isn’t needed when the car is moving. Following the fan, the next potential culprit is the radiator. You’ll want to check if it is clogged internally or if the external fans are blocked.

Next and more extreme are the water pump and head gaskets. Many jump right to thinking they have a head gasket failure without checking all the parts I listed before.

For these symptoms there are many different possibilities, so my best recommendation would be best to have an expert go through the correct sequence of tests in order to diagnose the overheating issue correctly before moving forward with repairs.

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