As the title says.....What is the normal coolant temperature range on a 6.0 L?

I bought my truck in December of 2012 and have never seen temperatures over 190 F. Tuesday coming home it spiked to 197 F and then went down to 190 F. I thumbed through the scangauge and looked at my fan speed and at idle it was 300. Which seems low. When the temp goes up to 197 at 45-70 the fan speed is always 380-450. I have been keeping an eye on the fan speed and at 70 MPH and coolant temp @ 188 the fan speed is between 744 and 800. Am I looking at replacing the fan clutch?

Later Tuesday night we went to go out for an errand and I had no power to the HVAC control on the dash. The back worked, but the front was blank and wouldn't turn on. I remembered seeing somewhere on here about the fan clutch or the plug could cause this. I unplugged it and plugged it back in and it worked when the truck was started 2 hours later. I have not had an issue since. Am I on the right track at all on this.

Lastly, what does black smoke on acceleration mean? Fuel not being burned?

I noticed a few weeks ago if I got on it hard to pass someone that it puffed a small cloud black smoke. I never noticed this when I bought it. I run diesel kleen fuel treatment. I just switched to the warm weather gray bottle.

So can anyone point me in the right direction? If I am having other issues that I am not seeing, I want to try and get to them before it gets bigger. The truck has 157K on it and is getting 15-17 MPG.

I have the following items due for maintenance:

Coolant flush and T-stat change.
Oil Change
Fuel filter change
Engine oil cooler R&R
EGR Delete.

 

From the Tech folder:

Recommended readings - Temperatures and Pressures

STOCK READINGS
Normal Severe Service Alarm
Tranny Temp 150 - 195 195 - 200 220
Coolant Temp 190 - 200 200 - 215 215+
Fuel Press 60 - 50 50 - 45 45
EGT - pre Turbo 650 - 1200 1200 - 1250 1300
EGT - post Turbo 700 900 1000
Boost 0 - 26 27 - 28 28
Oil Temp 200 - 215 215 - 230 230+


READINGS WITH TUNERS
Normal Severe Service Alarm
Tranny Temp 150 - 195 195 - 220 230
Coolant Temp 190 - 215 215 - 220 220+
Fuel Press 60 - 50 50 - 45 45
EGT - pre Turbo 650 - 1200 1200 - 1300 1300
EGT - post Turbo 700 900 1000
Boost 0 - 26 27 - 30 30+
Oil Temp 200 - 230 230 - 235 235+

Some say fan kicks on at 210, some say 215, others say 220. Full explanation: Engine temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that you will see some variation in engine temperature as it correlates to fan operation. The operation/description of the FSS (Fan Speed Sensor) from the PC/ED manual has a fairly good explanation as to how the system "thinks". This is not your traditional engine hits temp X and the fan clutch locks up. The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor sensor inputs and control the VDF speed based upon engine coolant temperature (ECT), transmission fluid temperature (TFT) and intake air temperature (IAT) requirements. When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF. Engine begins to defuel at 221 deg. The thermostat begins to open at about 190*F to 195*F and is not fully open until about 215*F to 219*F..

Sounds like it's time for a thermostat. It's opening a little early. It's common for that to happen. Black smoke can mean it's a little rich on throttle "tip in" but it's more than likely just soot. It's good to blow that stuff out of there from time to time .