Overheating towing a load

[Cllake]

I am having a problem with my truck overheating ONLY while towing a trailer.

Last month I towed my offroad truck, weighs about 5.5k with the trailer and my truck almost overheated(caught it before it got too hot). I pulled over and realized the PO JB welded the overflow back together as it was cracked and leaking coolant. I replaced that and had no problems.

Now my buddies mom needed me to tow her car from Phoenix to Prescott(pretty steep grades) yesterday. The cars GVWR is 2700ish and my trailer is probably 2k tops. My damn truck overheated again! There was no immediate place to pull over so it was ran in the red for about 3-5 minutes. Let it cool down and topped the system off(lost about 1 gallon). The rest of the trip I had to BABY the throttle and creep up hills, little hills. Once I dropped the car off there were no problems. Truck never gets remotely hot towing the empty trailer or WOT around town.


Fan is spinning, water-pump is returning coolant to the overflow and the coolant was just flushed last week. Any ideas what this could be?

Thanks for your help

Cody

[Cllake]

Here is what I was towing.

[Cllake]

Forget to include truck specs:

E99, auto, PHP tunes, DIY intake, stock exhaust. I was towing in the daily tune until I noticed the temps, then I went to the Stock setting. Truck is on 285/65/20, basically 35s with 3.73s.

[bruce51d]

check the fan clutch

[stickk]

Also check the degas cap. If it won't hold pressure it can cause premature overheating/boiling coolant.

[Cllake]

Originally Posted by bruce51d

check the fan clutch

.

How do I do this?

Originally Posted by stickk

Also check the degas cap. If it won't hold pressure it can cause premature overheating/boiling coolant.

The coolant was boiling out from the cap. I assumed that is where it should come from when overheating? How can I check if it is holding pressure?

Thanks for your help guys

[bruce51d]

if the engine is warm and you shut it down it it stops with the engine its shot, or if you shut it off and try to move it by hand with no avail its shot

[stickk]

Fan clutch-IIRC- with engine off spin the fan by hand. There should be some resistance, more when cold. Also, you should be able to hear it pretty well when towing, off and on. I think it is controlled electronically based on engine temp.

Coolant cap-have it tested. I don't know where/who has a tester but some auto shop should.

check this

$5 PART WILL SAVE YOUR POWERSTROKE FROM SELF DESTRUCTION - YouTube

$5 PART WILL SAVE YOUR POWERSTROKE FROM SELF DESTRUCTION - YouTube

[Cllake]

Originally Posted by bruce51d

if the engine is warm and you shut it down it it stops with the engine its shot, or if you shut it off and try to move it by hand with no avail its shot

I can move it with the truck off, there is resistance but it moves. Tried that when I was looking at it yesterday.

Originally Posted by stickk

Fan clutch-IIRC- with engine off spin the fan by hand. There should be some resistance, more when cold. Also, you should be able to hear it pretty well when towing, off and on. I think it is controlled electronically based on engine temp.

Coolant cap-have it tested. I don't know where/who has a tester but some auto shop should.

check this

$5 PART WILL SAVE YOUR POWERSTROKE FROM SELF DESTRUCTION - YouTube

It looks to be the original cap from 99! It cant be that simpe... lol

[NoRalPh]

Wait a min.... This test sounds Backwards to me

When the engine is Cold, and you don't need air moving through the radiator for cooling, the fan should spin with less resistance because the clutch isn't engaged (as much).

When the engine is Hot, and cooling is requiring air to be pulled through the radiator, the fan should spin with more resistance because the clutch is More engaged.

So, on an engine whos temperature is now hot, the theoretical Ideal (but I realize this doesn't actually happen with this clutch) would be that it Should STOP with the engine?? - No?

The whole idea of the clutch is that it requires Real HP to turn that Big Fan all the time and, the clutch makes the fan work only when necessary.