Cooling fans will only turn on if engine is off only

bad cooling fan motor.

Look at the cooling fan when the coolent gets hot the fan shod come on

check the radiator fan , maybe dont work

It could be the water pump. To check this:

• Make sure the engine is not hot and open up the radiator cap.
• Turn on the car and let it idle with the cap off.
• Allow the car to warm up.
• When the engine is hot and it is getting close to overheating, look down into the radiator. The coolant should flow. (It should look like a little river is going past the radiator opening). If the coolant appears to be still then your water pump is bad.

Other possible problems:

• Bad coolant temperature sensor.
• Air bubble in the cooling system.

Turn on the heater and see if it cools down a little or at all.

check clutch fan may not be engaging due to wear not turning fan fast enough,
radiator may be partly clogged. try lower temp termostat. try dexcool instead of regular antifreeze with water. hopefully your not using only water
that can cause your engine to over heat in certain conditions.

I take it this only happens when the vehicle is stopped & idling? If not, check radiator & hoses for blockage (since you've already replaced the thermostat & top hose) - repair/replace as needed. Next, check the coolant temperature sensor's operation (there are two sensors - one for the temp gauge on the instrument panel, the other is used by the ECM (PCM). If that one is malfunctioning (i.e., telling the computer that the engine coolant temperature is less than it actually is, The ECM (PCM) it won't turn on the cooling fans.
Since you didn't specify which engine you have (i.e., 2.4, 2.6 or 3.5), Photo locations of all three are included here.


Hope this helps.

Ok, fans work but you should replace temp. sensor so they come on automatic. If the temp gauge inside the car is getting really hot its either because the termostat is stuck closed or your water pump is pumping water to circulate it through the radiator and engine

GET COOLING FANS CHECKED SOUNDS LIKE A DODGEY FAN OR FAN SWITCH

Check your AC relay. This relay get weak through the years. Tap it a bit. To see if it makes a difference. Also check the Thermal Control Sensor. Have the car scanned for a code.Free at AutoZone.