Towed into the mountains of NC yesterday. While monitoring my OBD port via wifi, I saw the radiator temperature hit 215. Going up a roughly 6 mile incline. Had it torque locked in 2nd running about 40. About 2800 rpm. Once at the top and coasting, it dropped back to the normal running temperature of 197 ish. Anyone else see this on their rig? Is that normal?

 

That is comparable to what mine runs. Seems normal.

 

Mine stays around 205 when towing in the mountains with an all time high of 213 once but that's doing 75mph uphill towing 7k pounds.

 

My 2.7 gets to 237 occasionally when I'm towing my 7000 pound trailer up mountains. Gauge stays in the middle though....comes right down after the hill crests.

 

By the way. I'm running the 5.4. I'm still curious about others experiences. Just thought it would be worth noting.

Also, seems to me the faster you're going, the cooler it would run. More air flowing through to cool the radiator.

 

If it were only a matter of more air through the radiator, then yes, faster would be better, but to make that additional speed the engine works far harder than it would at, say 35-45 MPH. And with the well-designed fan clutches, shrouds, and sometimes additional electric fans most new trucks come with, they can emulate high volume airflow even at low speeds. So essentially, slower is better for cooling. HP=Heat. Max out the HP request and you're maxing out their ability to shed the heat as well. Saturation eventuality causes them to climb in temp.

 

I spent a couple Autumns driving sugar beet trucks, an M11 Cummins won't even turn on the radiator fan until 215°. You're fine.

Make sure your coolant system pressure cap is working, though. Most of them don't, and at 4PSI or less you run the risk of boiling/hot-spotting/blowing head gaskets.

 

Should be fine as long as it goes back down afterwards. Trans temp is something that should be monitored more I think. My 2.7 seems to kick the radiator fan on high when my trailer is connected, even with the engine not being warm. I'm guessing it's designed to do that when it senses a trailer connected...


If your temps get into the red on your dash when climbing, you'll definitely want to pull over and let it cool down. Don't turn off the truck, just put it in park and open the hood to let some heat out and let the fan do its work. Otherwise it should be fine.

 

Did the Ozarks in Missouri this past weekend.
On a three mile climb my 2008 5.4 hit 219 degrees on coolant temp. Cruise was ON and truck held 64 MPH @ 4000 RPM.
Truck was doing 215 degrees just cruising at 64 MPH.
Truck is a 2008 FX4 5.4 SCREW with 135,XXX miles.

 

At what tranny temp should we be concerned damage may occur (6 speed transmission)? I hit 104C (219F) going up a pass towing a 6000lb TT (I should also note I was passing a Ecoboost towing a TT, hehe). I was maintaining a steady speed of 55mph.

I like to check the tranny temp when climbing, and have note seen it go past 104C. Once the road levels off or starts to decline the temp always drops immediately.