6.0 overheating but no coolant loss

[legends13]

I have a 2005 CC xlt 6.0, and it has been a great truck. Had the oil cooler, egr cooler replaced back at about 70k, and now has 155k. For the past 6 months, when I tow, (approx 6000 lbs enclosed race trailer) I have been getting overheat issues. If I keep the speed under 70mph, and light or no grade, the truck is fine. If I get on a bigger hill, or try to maintain over 70mph, the truck starts to overheat. My Ect/eot split is not huge. Maybe 15-20 at the most. When the temp starts to go up, the fan comes on, and as long as I let up a bit, the temps come down. Occasionally it will get the Ect up to around 240 though. I am not losing any coolant, and have the degas level right where it should be. I use 10w30 rotella semi-synthetic oil, and have done coolant flush and added the coolant filter.

Any ideas what might be wrong?

[ZMANN]

whats overheat temp ? EDIT I see 240

6.0 can loose water pump blades/ have t stat issue ETC

[dannyboy950]

Check your air flow; check for restriction;trash;dirty collapsed fins on the condensor;air cooler and radiator. When you flushed did you have the radiator checked/cleaned?
Check your coolant filter may be clogged. I suspect the radiator cores are restricted.

Your deltas are in the danger zone and your ECT is at the coolant boiling point at 240 deg. F What is your actual EOT temps?

Along with zman's info that cover everything but improper fan operation.

[legends13]

EOT is getting up to 230 at times, but not really much higher. At least not that I can recall. also, the EOT/ECT split is only about 7-12 when using as my daily driver. It is only under load where the split gets larger.

No, I haven't had the radiator checked. When you say the cores are restricted, do you mean internally or externally? Is it something that the radiator could be pulled and hosed out? I know the fan kicks on and goes up to around 2500RPM when the water starts to get hot, so it seems like the fan is working.

[Pistolgrip426]

Had same issues,new radiator,fixed her up,try to get an all aluminum one.

[legends13]

Ok, more info. I had 2 mechanics check out the truck. The first one is a Ford diesel tech at a large dealership, who also does work on the side. He said he pressure checked the coolant system, and it pushed over 30psi and that I have a bad head gasket. The second guy is a local mechanic that does a lot of diesel work. He said he pressure checked and only got up to 16psi. He says it isn't a head gasket, but more likely something with the fan or radiator. I really don't know who to believe. I hate to spend the money on head gaskets if it isn't needed, but I also don't want to spend money on fan and radiator just to still have an issue with head gaskets. Anyone got any other ideas???

Should I get a pressure Guage and just check it myself? If so, what should I see? I know powerstrokehelp.com has a video showing how to check, but I also have heard he doesn't really know what he's talking about....

[southend]

If eot and ect are climbing together, your water pump is probably bad. I would quit running it like that.....

Sent from my phone that somebody didn't help me get.