2019 6.7 towing 42 ft fifth wheel
 

Was towing my Grand Design 42 ft fifth wheel in Colorado, not in the mountains. But on some inclines. I noticed some engine heating, and had to seriously slow down. My f-350 is a single rear short bed. Trying to figure out why it would start overheating

What kind of temps were you seeing?

Like where in CO are we talking about?

What temperature were you seeing?

What is the actual weight of your trailer as you were having this issue?

Just because the clutch fan comes on high and you see the temp guage rise to the other side of center does not mean it is overheating.

At that spot your coolant is only about 220F if you put a guage on it.

Oil temps are fine up to 248F and you were not there.

With my 2013 I could take Monarch pass at speed or even the Eisenhower Pass without issue.

If the clutch fan comes on like an airplane then let it do its thing.

If this is abnormal for your truck and camper you may have been facing a very stiff headwind without realizing it due to power of the truck. The truck may have been working harder than you realized. Couple years ago our truck was running warmer than normal and fuel economy was way down. Then I realized the grass was blowing down flat in the opposite direction !

Doesn't hurt to make sure the engine air filter is clean and spray a garden hose both directions through the cooling stack. Even if the A/C condenser, intercooler, and radiator look clean, fine dust can build up and make a difference.

First, .

Then let us know what, exactly, you thought was overheating (water, oil, transmission).

Like most folks said - these things run hot. Ford designed it that way.

Good advise! I agree with everything said about Ford and higher temps. Had a similar situation on the IKE, not with my Powerstroke but with my old F150 pulling a 6k trailer. Should have been fine weight-wise and I had done the trip many times before. What I didn't notice, was that my coolant was empty. It was full before the first leg of my climb and empty by the second leg up the IKE. Come to find out those coolant caps are cheap and they wear and under pressure quit and empty your coolant very quickly. It's hard to miss though if you pop the hood and see what's left of the coolant vaporizing. I thought I had big issues with my coolant system but turns out it was a <$5 cap.

My truck got hotter than normal, the actual temp showed up above the ECT gauge, the fan engaged and the engine derated. Once over the pass the ECT dropped and all went back to normal. It was 113⁰ in the shade towing a 16k boat up a 7% grade.

Make sure your secondary coolant reservoir is topped off as well

And what makes you think it derated in power?