I have done the EGR delete....cooler is gone . Been about 20,000 miles since doing so . I have 198,00 miles and recently towed my 5ver for about 5 hours . At the campground checked and I was 1 gal. low on coolant . Degas bottle looked fine...oil looked fine . Added 1 gal. and on way home my water temp. spiked to 240 and went right back down . I pulled in and added another Gal. of coolant . This was after about 1.5 hrs. of running . .....I have an SCT tuner , BUT I go back to stock setting when towing . Only have it for better fuel mileage...never get into it . I pulled 2 codes....P0299...turbo under-boost and P0478...exhaust pressure control valve A . The truck gave an engine overheat ( idiot gauge did not ) and decelerated . Did the rest of the trip home...3.5 hrs. and all temps looked fine and was running in the hills... lost less than 1/2 gal. for the second have of trip .
Any idea's ??? Crawled all over engine and did not see any signs of leaks . When I pulled in there was signs that it came out around cap....coolant on battery and drivers side inner fender . And on outside of tire. Cap is fairly new .
While looking I did see my heater hose had been rubbing against the valve cover corner and was about to rub through . I pulled hose off today...washed down engine really good and waiting for a new hose . I am kinda nervous about running it as I have a long road trip end of the week .

 

I'd do a coolant preasure test and see what your pressures are. Sounds like possible blown head gasket. Coolant in the mortar compartment says you have way to much coolant preasure.

 

Did a pressure test...got up to 16-17 psi...temp.was 194.....

 

Check this radiator hose under degas bottle. The y joint is known to crack. And also it tends to rub on back of valve cover and puncher.
I'd also take a close look at the little blue egr hose coming off your oil cooler in the valley. Look to see if there's any coolant in your valley.

 

Heater hose was worn really bad...replaced that,but wasn't leaking. Didn't see anything in v.....the y showed no signs of leaks. So is that pressure alright in degas bottle...? Thought if it got above 15 it might be head gaskets ? Just started losing water on that lasted tow..definitely some came out cap but not 2.5 gal...and don't see any obvious leaking. Changed cap before testing pressure. Short hill climb..not towing...

 

16 - 17 in my opinion is not that bad. Other guys might think different. Are you sure you don't see no spots on the driveway? that's a lot of coolant not to have no spots on driveway. Have you looked at water pump?
I think in your position I would park on a clean place and let sit and idle up to temp and look for any spots big or small. You could also use a dye and black light, that will defiantly find it, if there is one.

 

The degas bottle cap is a pressure relief device. The OEM cap is set to relieve pressure at around 16 psig. So even if you try to pressure it up higher, it will just open up to let the vapor out.

So if 16 - 17 is what you got when driving, it is probably not going any higher because it is venting. IMO that is possibly indicating a head gasket problem.

I also believe that if you were to go much higher in pressure, you risk the OEM radiator "splitting a seam".

 

Very probable it's HGs + cyl head cracks (>90% of all 6.0Ls have them or will get them) ---try using Fel Pro HGs when you fix the prob and be surgery ward clean when in there doing the fixes --- cleanliness is very important during R&Rs.

 

Was planning to stud the engine next year..guess it's going to be this year. I was retiring next year and could have done it, but don't have time now...talked to a reputable highly recommended shop and will be having it done there.......

 

If you don't mind me asking? What did they give for a quote? My truck hasn't been studded yet but I'm sure it's coming. I only have 116000 miles on it and it runs great , but I know it needs to be done. I can do it my self but would have to do it in my drive. Not looking forward to it. If this covid scam will go away and I can get back to full work in my buessines, I'll pay and have it done, if not I'll do it myself.