Clutch fan

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

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?

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.

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.

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.