# overheating when idle



## buckeyes (Nov 20, 2014)

Hello guys I was wondering if anyone has had this problem. I have an 06 frontier LE v6 (78,000 miles). I am currently having an issue of the truck over heating in stopped traffic, when I give it fuel or start moving again it cools back down, was wondering if It is a water pump or a sensor gone bad.

Thanks for the help


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## Roader (Nov 9, 2014)

Coolant full up?


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## buckeyes (Nov 20, 2014)

Yes coolant is full, thermostat 4 months old, radiator 4 months old, did coolant flush 4 months ago


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## smj999smj (Jan 1, 2006)

Your symptoms point to a bad fan clutch. When you are sitting still or in slow traffic, the fan needs to turn fast enough to pull sufficient air through the radiator and condenser cores. If the clutch is not engaging the fan to turn fast enough, it will cause overheating. When the vehicle is driving down the road, there is sufficient airflow being forced through the cores to cool the coolant.


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## buckeyes (Nov 20, 2014)

So when I give it fuel it spins the fan clutch faster?


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## smj999smj (Jan 1, 2006)

When the engine turns faster, the input shaft of the clutch assy. turns faster. The fan is attached to the clutch assy. How fast the fan turns in relation to the input shaft speed is dependent on how much the clutch engages. There are different types of clutches: thermal and non-thermal, fluid-type (the most common) and electric. They all serve the same function, to allow the fan to be operational at low speeds and to disconnect at higher speeds, which takes a load off of the engine and is better for power and better gas mileage. If the clutch locks up, it will work the same as a fixed fan and usually be on the noisy side. If the clutch doesn't fully engage at low speeds, which sounds like what it happening in your case, the fan won't spin pull enough air through the radiator core to allow the coolant to be cooled sufficiently.


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## Cusser (Apr 16, 2004)

smj999smj said:


> Your symptoms point to a bad fan clutch. When you are sitting still or in slow traffic, the fan needs to turn fast enough to pull sufficient air through the radiator and condenser cores. If the clutch is not engaging the fan to turn fast enough, it will cause overheating. When the vehicle is driving down the road, there is sufficient airflow being forced through the cores to cool the coolant.


Running hot at idle or traffic but OK at higher speeds indicates bad fan clutch, typical, like he stated. Or on vehicles with electric fan(s): fan not spinning when it should be (bad fan or thermostatic control).


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