I have a 2008 6.4 diesel. I bought the truck a few months back from a guy that rebuilt the motor. He also had a tuner in the truck that showed a code for clutch fan. He gave me a used one he had lying around. I forgot all about this issue as the truck had no temperature issues in daily driving. I went on a hunting trip and was climbing a long hill in low range. I glanced at my tuner and coolant was about 225 with oil temp higher. I spun it around and headed downhill which had the temp drop immediately. Back home I replaced the clutch unit on the fan. As soon as I drove the truck it kicked in right off the bat for 30 seconds or so. I have never had it kick in again. I was towing uphill yesterday and saw the coolant was about 219 on my tuner as I crested the hill. When should my fan kick in?? The factory coolant gauge was well within the normal range. Thanks

 

Moved to the 6.4L forum.

 

Man I think it would turn on way before that. I have my tuner set to defuel my truck at 210* with coolant and oil temp which is what H&S recommended. As for an answer I don't know if it has a certain temp or what to kick on and I don't know what that would be.

As for the factory gauges, I've learned not to trust them. Mine will say my truck is at working temps but I'll look at my monitor and my coolant will be at 150? Hope you find an answer.

 

It's roughly the same as the 6.0L: ~220*f ECT, plus there are other parameters that include EOT, TFT, but seems like ther 6.4L has more things that trigger it.

You can 1) find someone with IDS or AE and command the fan clutch to 100% duty cycle to see if it can lock in at all, 2) talk to a tune writer and see if the fan clutch duty cycle is something they can edit in the PCM tuning. The only issue with #2 is did your truck come with the tuner that was used for the deletes, because if you have to buy a tuner you'll have to buy an unlcked used one that has legacy support for the DPF delete. New tuners cannot delete the DPF, Edge and H&S found that out the hard way.

 

I recently put a custom tune in mine. Never thought about asking about clutch fan.