Have a 2006 F250 6.0. EOT ran around 225-240 at 65mph. ECT stayed between 210-222. On incline EOT climbs easily if I push it at all. Max EOT i saw was 252.4, max ECT of 246. That was after a large hill, at the peak. Slowed down and both came down in the range i mention above.

This was over a 30 mile stretch of large rolling hills. Lost a gallon of coolant, but did not puke it out of degas bottle. Checked oil and doesn’t look milky from dipstick.

after the rolling hills I added a gallon of coolant and drove roughly 120 miles of flat roads at/undee 70 mph no problem.

The engine is stock and has 160k miles. Just want some direction on what I need to do to fix this. Thermostat, fan clutch, oil cooler, head gaskets? EGR Delete?

Thanks

 

I'd slow down going up those hills when it's so hot out.

 

are your temperatures often in this range? If so, they will cause problems. I look for an EOT of 220°F/105°C max. in my truck. I always keep an eye on the values on climbs. Maybe something is wrong with your fan clutch, radiator, oil cooler or water pump, you should take care of it.

 

I know something is wrong, haven’t owned the truck long, was the first longer trip towing something.

any advice on how to narrow down what the issue might be?

 

That was slowing down and ambient temp was 75 degrees out.

 

The first likely culprit, since you don't mention a freight train running you off the road, is the fan clutch. It should have been screaming so loud and dragging down so much HP that you couldn't have stood driving very long. It is a common failure from mileage or years. If you can monitor fan speed while driving, you can clearly see it when it starts speeding up and slowing down. Although many factors affect fan speed, I've never seen any of my trucks fail to kick the fan on by 224 unless the clutch was broke.

That said, other things to check are the wiring going to the temp sensors and the sensors themselves. After a long cool off to stone cold, are the temp-based sensors all close to the same near-ambient temperature? And, of course, there are the cooling system components - the radiator, water pump, and thermostat. Or the AC condenser caked with mud blocking air flow. Nothing you've described has eliminated anything for me, but others are much more knowledgeable.

I'm just concerned that you kept driving at those temps. The truck was about to defuel. I've been able to get my trucks over some pretty high mountains pulling some decent-sized loads with pretty lame cooling systems without ever getting that hot. It really helps to drive aggressively...aggressively slow. So slow that you'll prolly **** people off, but just the jerks. Most people give trucks towing up hills a bye on speed.

I can't be sure how or if my strategy works, but it seems to be. Importantly, it requires that you react early, slow down well before your temps start the climb that they're going to make regardless. Milk that rise to take as long as you can. I've found that keeping the RPMs around 1800-2000 tops even though it can slow me down to under 30mph, generally keeps the truck below 230 up most of the long inclines. If you do have to pull over to cool down, don't kill the engine, and actually idle high to keep coolant flowing. Disclaimer: I say all that, but not sure if a bad fan changes that strategy.

 

How big is your trailer? The fan will generally kick on low speed around 208F ECT and high speed around 220F ECT. Can't always hear low speed, but high speed you cannot miss. If it's not you've got clutch or wiring issues as described by Commie above.

 

I think I heard the Fan kick in but I don’t think it was consistently running at the right set points.

I’m gonna start with checking the Fan and do a pressure test on the coolant system. I have noticed excessive moisture coming from under the passenger side of engine when running, but I chalked it up to being condensation from A/C. Now Im thinking it is something else. Didn’t smell like coolant but now Im thinking it might be.

 

If I remember right I believe forscan will engage the fan, makes for an easy way to check it.

 

Oil coolers last around 100k. You're due for a replacement.

 

The Camper weighs 6700lbs.

 

I made this video last year. At overtemp your fan should sound like this.

 

"Excessive moisture" - eek. Hope this works out.

 

yeah, I’m definitely not hearing this. That makes me think it is the fan clutch. Still not sure it explains the coolant loss though.

 

EGR leaks is your best hope. If it is deleted or not the cause, only puking or leaking is your second hope. Other than that, it is the head gasket that eats coolant. But .... if you had low coolant for a long time and not aware of it, then it is just showing up.