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Q: Temperature needles moves to "hot" when idle but goes back to "cold" when moving.

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Our temperature needle always goes to the red line when we are idle, only. If we are moving, it stays closer to the "c". If we stay idle and the needle goes to red the low coolant light comes on and keeps dinging until we move again. As soon as we move, the needle moves. There is never any smoke coming from the hood nor does it ever smell as if it's running hot. Also, our heat starts blowing cool air when idle. Today, the vehicle started shaking. Could all of these problem be related?

My car has 140000 miles.
My car has an automatic transmission.

A: The engine temperature fluctuating as it is...

The engine temperature fluctuating as it is can be caused by a number of components or problems. If the cooling system is restricted, coolant flow may be reduced at low engine speeds (idle) and be better when moving. If the cooling system has not been serviced for a long period, coolant passages in the radiator, heater, and engine may be restricted enough to limit coolant flow. Low coolant level can cause similar symptoms. Also, electrical issues can cause the vehicle to run hot at low speeds. If the radiator cooling fan is not turning on, the temperature will rise until you begin moving again, getting air flow through the radiator.

Have a certified technician diagnose the running hot issues as soon as possible. Running hot can cause performance issues as well as severe damage to the engine.

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