Coolant Temp When Towing

I have noticed that when towing the coolant temp rises to the max within about 10 seconds under the following conditions:

- 105F ambient temperature
- towing 30ft, 6,000lb trailer
- slight uphill incline
- 4th gear
- 2,600 RPM
- 60 - 65 MPH
- tow/haul mode turned on

As soon as I get to a level section of road then it drops just as fast back to normal. Uphill only has to be very slight to cause the temperature to increase.

Is this normal or abnormal?

If I lock out 6th, 5th and 4th gears, forcing it into 3rd, then the engine speed increases to 3,600 RPM and the temperature holds steady or drops.

If I force it into 2nd gear then the temperature increases.

In all conditions I have plenty of power and can easily accelerate to any speed I want/need. Trans and oil temp are fine.

So to get the most out the capabilities of my vehicle (2016, Limited, HD tow package) am I right in thinking:

- use transmission's choice of gear unless temperature rises
- if temperature rises then drop down one gear
- if dropping down one gear still causes temperature to rise then slow down until temperature holds steady or drops

?

Thanks! Andy

The engine likes to use boost instead of downshifting. Use a lower gear if you see coolant temps rising. Downshifting will reduce the load on the engine and run the water pump harder.

OK, many thanks. When towing I was keeping it on the distance to empty screen but now I keep it on the screen that shows coolant temp instead.

If it isn't boiling over there should be no problem. I let the truck handle all this by itself. There's a computer there with lots of sensors and programming.

I don't recall what the display indicates is the "Maximum temperature." But Max is still in spec. When I logged my temperatures crossing the PA mountains a couple years ago they stayed right about 200° (flat line graph +/- 5°) towing my 23ft travel trailer.

220°F isn't unreasonably high and while 50-50 antifreeze will boil at just over that temperature in an unpressurized system the boiling point is raised another 45° to about 265° compensate if the radiator cap is on.

-- Chuck

Have a 2018 max - everytime I’m traveling 70mph+ and pass someone temp goes to 235,237,239 and then when I slow down goes back to normal. At first it freaked me out and took it to dealer (horrible first two experiences, incompetent ford “technician”). Finally went to different ford dealer and the head mechanic got on the phone with ford engineers who told him that the eco boost engine is supposed to run that way- not to worry. Hope that helps

I have a 2014 Limited with HD tow. My analog temp gauge doesn’t budge climbing the Cascades or Sierras. And those Mtn ranges are seriously steep! That said I don’t try to climb a steep grade above 3000 rpm. I’m happy to stay in the truck lane or take pull outs.

Thanks for the replies. When it reaches max temp the vehicle shows an alert telling me that the temp is too high and the power has been reduced. May be in spec but still a bit scary to see that.

Thanks -- neither of my Expeditions has ever got that hot. Are you letting the truck manage gears when this happens? I've never tried to out-guess mine.

-- Chuck

chuck s said:

Thanks -- neither of my Expeditions has ever got that hot. Are you letting the truck manage gears when this happens? I've never tried to out-guess mine.

-- Chuck

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Yes.

Have 2018 with heavy duty tow, this year started seeing temperature numbers appear above the temp bar graph when driving 80 mph into a headwind or driving 75 mph pulling my 21’ boat. Truck was showing 228 to 234 degrees. Upon slowing down slightly, temp numbers would quickly disappear. Owned truck since New and this has never happened before. I had cam phasers done and water pump replaced, both by Ford Dealer under extended warranty.
I just had my dealer replace my thermostat (approx $350 repair). Two dealers said it is very rare to have thermostat failures. In driving around town, I think my radiator fans are running at much lower rom’s. I hace not pulled our boat or been on a road trip to test under higher loads, but honestly I think replacing the thermostat fixed my problem.