How much water in the fuel must there be to trip the WIF light on a 6.0? My WIF light keeps coming and going. I have replaced the fuel filter, and drained the HFCM again after the filter change. I it taking longer to come back on, but it comes back. I don't see any water in what I have drained. I have also put White Bottle power service, and also so 911 power service I had. Could this be an actual water issue, or some other issue. This all started after a big temp swing over a few days, like 50,20,50,20 swing....... The truck is running fine, no loss of power, and no other lights but the WIF.....