Cracked head or liner?

[Mluper]

Hey guys. I have a question for you. I have a ISX manufactured in 12/2006. I had the unmentionable done to my ECM for after treatment issues system. Only came with the egr no DPF. Anyways before I had that done I had new injectors installed and my intake rocker arms rebuilt. Then I went out for s run and noticed I had low oil pressure spikes. I brought it back to Kenworth and we tore the oil pan off and noticed my oil pump pick up tube connection was severed. So we replaced the pump and checked main and rod bearing. All looked great. 2 months after I had the thing done to my ECM and we plugged off the system with freez plugs. My egr was bad and cooler had just started to leak. I've been running my truck like that for four months. Now my engine is pressurizing my coolant system some how and I'm affraid it's gunna be really expensive. No coolant in the oil. No oil in the coolant. It blows bubbles out the overflow tube off the radiator cap when I submerge it into a water bottle. It won't do it when I start the truck cold. It has to be around operating temp. If I'm pulling a load and get the temp up the bubbles are intense. Otherwise just a moderate bloop bloop when at normal temp. That leads me to believe it's heat/metal involved so I'm wondering if anyone has any suggestions or seen this before.