What is a car overheating temperature?

Why does my temperature guage go up to overheating when i start my car and accelerate but goes back to normal?

• I have a 2002 cheep grand Cherokee. When I start my car the temperature gauge is half way between normal (the middle) and overheating.. The engine coolant is filled. When I accelerate ...show more

• Answer:

  This is normal. When your car is running and not moving, the coolant is circulated through the system, but NO AIR is moving through the radiator to cool it down. When the car is moving, the air flowing through the radiator cools it down then it is circulated back to the engine (through the lower hose). When you rev the engine, you are increasing the rate that the coolant flows to the radiator, BUT it will not be cooled much due to the lack of airflow. You may notice a slight decrease in temperature, but this will spike since revving the engine generates heat faster than idling it. If then temperature rises enough, then you should hear the cooling fan come on, this will lower the engine temperature just like driving around would but once the temperature has lowered enough, then the fan will shut off and the temp will rise again. If your cooling fan is not working, or if you notice the temperature enter the red area, then either drive the car to cool it down or pull over and shut the engine off, as damage to the engine and cooling system may result.