Help me figure this out

[pa05stroker]

My dad has an 04 6.0 160,000 on the clock. The only problem that hes had to fix was a head gasket like 2 years after he had the truck, 4 injecters,and a turbo tube. The truck is his daily driver and gets used most days at work. He doesn't pull all the time but fairly often. And never a whole lot of weight. Mostly his 16' trailer with a couple 4wheelers on it. But here's the problem. Whenever pulling it takes very little for his high speed fan to kick on. The smallest hills make it kick on and of stays on for awhile. I talked him into buying a cts the other month. Last week we hauled a small tractor and a 4 wheeler to camp. Maybe 8000 lbs. And we were goin up a pretty steep hill his fan kicked on at the bottom his eot going up the hill was 248 and his coolant was around 216. What do you guys think?

[taskforcefreddy]

There can be a lot of factors contributing to higher ECT's. How hot was it outside? How old is the coolant? Has it ever been flushed? How about the oil cooler? Better yet, what are his temps when NOT pulling a trailer? Keep in mind that anything over a 15 degree difference when on a flat surface with no load at 65mph is an indicator of a clogged oil cooler. I know my fan runs quite a bit when towing my boat at highway speeds... especially when it's hot out.

[pa05stroker]

Idk if his coolant has ever been changed or flushed yet at it. And it was like 85 degrees out when we took that. Were goin on a road trip to Ohio this weekend and ill get a unloaded delta to see what its like. I just know I've pulled the same amount of weight and my uncle has pulled more than that with our 6.0s up the same roads with a higher ambient temp and neither of our fans even kicked on.

[bismic]

Change the oil cooler before it fails.

Flush the coolant system. Do some searching on coolant posts and choose what type you want to go with (Ford Gold or ELC are the most common choices)

[taskforcefreddy]

Yeah man. Do a search on here as to what a clogged oil cooler can do to your truck and you'll see that it needs to be diagnised and fixed ASAP. Before doing that though, consider flushing the old coolant out for an ELC type coolant designed for diesels. You will see that an ELC coolant lacks the silicates that have a tendancy to clog up the oil cooler which can eventually lead to head gasket failure. Also, check the degas bottle. Is there any white residue around the cap? Keep an eye on your coolant level as well.

[pa05stroker]

Well id say dads truck needs a new oil cooler. 65 out the highway as we speak eot is 211 ect is 190 ambient temp 80 degrees.

[lenzhotrod]

Oil cooler time.