Clutch fan

2008 FORD F-250
168,000 MILES • 6.4L • V8 • TURBO • 4WD • AUTOMATIC
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GOAT6970
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Is there supposed to be a constant drag on the fan? it has a drag on the first 2-3 revolutions then it free spins (engine is off). I’m asking because my truck doesn’t over heat but blows fluid out of the overflow tank at 204 def truck normally runs at 192-195 but except on hills it’ll run higher but never over 208.
Sep 18, 2019 at 1:11 PM
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KASEKENNY
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Hi,

Yes. You should be feeling resistance. This is the clutch inside. If there is no resistance then the clutch as failed so that sounds okay. Also, the fact that it doesn't get above 208 sounds like it is operating.

https://www.2carpros.com/articles/fan-clutch-symptoms

However, the issue is most likely a head issue. The added pressure is probably coming from the combustion chamber. Best thing to do is put a pressure gauge in line on the small line from the de-gas bottle and radiator. It shouldn't be more than about 15-18 PSI.

It could also be something in the EGR system but lets start there. Unfortunately, this is pretty common on the 6.4L and 6.0L.

Let me know what you find and we can go from there. Thanks
Sep 18, 2019 at 5:58 PM
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GOAT6970
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It has been deleted .
Sep 19, 2019 at 7:23 AM
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KASEKENNY
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Okay. Then clearly we need to focus on the head issue. Do you have a programmer on it as well that is adding horse power?
Sep 19, 2019 at 6:44 PM
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GOAT6970
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Yes, but I keep it on stock because I wanted to delete the exhaust. I pull a toy hauler got tired of it going into regen constantly.
Sep 20, 2019 at 8:34 AM
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KASEKENNY
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Okay. Understandable. The main reason I ask is when people delete EGR and DPF systems but don't "tell" the PCM it throws off fueling a bit and it is more common to see overheating and head warping. Also, when they are adding power to the engine it simple blows the head gasket because of all the extra heat.
Sep 20, 2019 at 6:45 PM
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GOAT6970
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That’s what I don’t understand is if it’s a head gasket it would overheat all the time which is my understanding on every vehicle I’ve ever worked on. just diesels are new to me. I’ve ran my truck all week and it’s only ever gone over 195 once. went I pulled our gutter trailer up about a quarter mile hill to a job.
Sep 21, 2019 at 10:35 PM
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KASEKENNY
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In general you are correct. A head gasket does not fail like a light switch. It normally takes a little while unless the vehicle is severely overheated and the head warps. However, if you have a head bolt that has been stretched by the expanding and constricting of the engine then it may be beginning to fail.

Normally coolant being pushed out of the coolant bottle on diesels is by excess pressure (head gaskets), too much coolant, or a failed seal on the cap. I didn't mention the last one before and I am not sure how I over looked the easiest possible cause. The bottle on your engine is what is called a de-gas bottle. Meaning it combines the radiator cap and overflow bottle. They have a seal on the inside and when that fails they leak.

I would replace that before we go any further. Let me know thanks.
Sep 22, 2019 at 1:33 PM
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GOAT6970
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So you are saying it could be the cap?
Oct 17, 2019 at 2:04 PM
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KASEKENNY
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Correct. The cap is responsible for regulating the pressure and it vents the pressure when it increases too much. However, it has a seal to not allow the coolant out. If that is leaking then it can let the coolant out causing a leak.
Oct 17, 2019 at 4:44 PM