Puking only when towing but no overheating

[atc500]

On a recent hunting trip pulling a goose neck (4,500LBS) 150 miles one way my truck started puking coolant i have a scangauge II and my max temps the whole drive was EOT 226 ECT 217 it lost over a gallon of coolant both ways +1 there and +1 on the way back it may have been a little over full on the way there, prior to the trip i hadn't been loosing coolant but had been smelling it in the cab so i replaced the heater core and the problem went away the truck has a no name egr delete kit Gearhead 8k sct tow tune,Stage 2 turbo truck runs fine idles smooth no loss of power starts up great with no smoke I'm just wondering if this is a minor head gasket leak and its only letting out under a load or if the egr delete kit is failing someway any advice to figure this out is appreciated Thanks also i forgot to add i had the Stant cap on on the way there and switched to the stock one on the way back with no change

 

[swinky]

Head gaskets. To be sure get your hands on a 5 or 4 gas analyzer and test coolant jug for carbon monoxide.

 

[dzldoctor]

Head gaskets. To be sure get your hands on a 5 or 4 gas analyzer and test coolant jug for carbon monoxide.

YEP

 

[Mdub707]

Sounds like every time I blew headgaskets. They usually don't lose any power, mine never really smoked at any point, and temps always stayed relatively normal. Coolant would rise quickly on big hills and what not, but it would come right back down on the other side. My guess is headgaskets too. I've only ever once had one fail so bad it was really obvious right then. What you're experiencing is how most of them are, typically.

 

[CodyC]

Same issue for me....head gasket failure....mine started puking and before I noticed a temp spike it popped the egr cooler line....studded and deleted it and now my y up pipe has a cracked bellow now....can never get ahead on these thing

 

[Trqmnstr]

Mine started barely puking, over/under boost codes and the limp light would turn on but it wouldnt go into limp mode. Gaskets where blown and egr cooler was about to go.