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my 2000 f150 5.4 is overheating when it idles for more than 5 mins, usually its when the temp is more than 90 degs F. Right before it starts to overheat is starts idiling alittle rough. Then when I go it cools right down, radiator? Fan? Any help woiuld be great thanks!
Is the fan clutch working normal?
Is the coolant level high enough?
Is the coolant bottle cap good?
Is the thermostat faulty?
Is the radiator bottom part plugged?
I would service all these areas and pay special; attention to the radiator being restricted.
Why, because you say it cools when you drive.
That indicates extra air is required to cool the restricted cooling area.
It would only get worse with time.
Good luck.
Fan clutch is thermally controlled.
Either it free wheels or is bound up and runs at all speeds.
In between these, you would have to force it by hand, slipping the clutch
A way to check for thermal operation is to connect a good 'clamp-on' timing light to one of the cylinders fuel injector's or coil cables allowing it to trigger the light.
With the motor running and heated, aim the light at the rotating fan blades.
As the fan clutch engages and disengages per the coolant temp changes the clutch senses, the fan blades will stobe to make them stand still then go out of strobe as the radiator temp changes via the thermostat operation.
You can see both these actions by proxiy and see if there is an issue to be addressed.
Try draining the radiator. If it is hard to get it to start draining, you most likely have a plugged condition.
Good luck.
fan should turn fairly easy when cold, and when motor is "hot", shut off and try to trun the fan... should have a lot of drag.. Best guess, is just put a new fan on it, if the radiator fins are clean and you can see thru it. IF you just speed the motor up to 1200 RPM setting still, does it start to cool ?